1. If cos A = 4 /5 , then the value of tan A is
ā ,Ā¾,4/3, 5/3
Explanation:
Cos A = 4/5 provided
The value of tan A must be determined.
We are aware that cos x = adjacent/hypotenuse.
Adjoining = 4
(5) Hypotenuse
(Hypotenuse) Using the Pythagorean Theorem2 equals (opposite)2 + (nearby)2.Ā² (5)2 = (contrary)Ā² + (4)Ā²
25 = (contrary)Ā²+ 16
(contrary)Ā² = 25 - 16
(contrary)Ā² = 9
Using the square root,
Contrary = 3
We are aware that tan A = opposite/nearby tan A = 3/4.
As a result, tan A has a value of 3/4.
2. If sin A = 1 /2, then the value of cot A is
(A) 3 (B) ā (C) 3/2 (D) 1
Explanation:
Provided that sin A = 0,
We need to determine what cot A is worth.
As we are aware, sin A = opposite and hypotenuse
Contrary = 1
2 Hypotenuse
(Hypotenuse) Using the Pythagorean Theorem2 = (contrary)Ā²+ (nearby)Ā² (2)Ā² = (contiguous)Ā² + (1)Ā²
4 = (contiguous)2 + 1 (nearby)Ā² = 4 - 1 (nearby)Ā² = 3
Using the square root,
Adjoining = 3
We are aware that cot A equals next to or across from
Cot A = ā3/1
Therefore, cot A has a value of 3.
3. The value of the expression [cosec (75Ā° + Īø) ā sec (15Ā° ā Īø) ā tan (55Ā° + Īø) + cot (35Ā° ā Īø)] is
(A) ā 1 (B) 0 (C) 1 (D) 3/2
Explanation:
The value of the formula [cosec (75Ā° + Īø) - sec (15Ā° - Īø ) - tan (55Ā° + Īø ) + cot (35Ā° - Īø )] must be determined.
Cosec A is known to equal sec (90Ā° - A).
Cot A also equals tan (90Ā° - A).
Cosec (75Ā° + Īø ) now equals sec (90Ā° - (75Ā° + Īø)) equals sec (15Ā° - Īø ), and cot (35Ā° - Īø ) equals tan (90Ā° - (35Ā° - )) equals tan (55Ā°+ ).
This means that [cosec (75Ā° + Īø) - sec (15Ā° - Īø) - tan (55Ā° + Īø) + cot (35Ā° - Īø)]
Tan (55Ā° + Īø ) + Tan (55Ā° + Īø ) = [sec (15Ā° + Īø) - sec (15Ā° - Īø ) - tan (55Ā° + Īø )]
= 0
As a result, the formula [cosec (75Ā° + Īø) - sec (15Ā° - Īø ) - tan (55Ā° + Īø) + cot (35Ā° - Īø )] has no value.
4. Given that sinĪø = a/b , then cosĪø is equal to
a. b/ā(bĀ²-aĀ²)
b. a/ā(bĀ²-aĀ²)
c. ā(bĀ²-aĀ²)/b
d. b/a
Explanation:
Since sin = a/b,
We must ascertain the cos valueĪø.
Knowing that sin A equals the reverse and hypotenuse
Contrary = a
b = hypotenuse
(Hypotenuse) Using the Pythagorean TheoremĀ² = (contrary)Ā² + (nearby)Ā² (b)Ā²= (contiguous)Ā² + (a)Ā² (contiguous)Ā² = bĀ² - aĀ²
Using the square root,
Adjoining = (bĀ² - a2), which
We are aware that adjacent/hypotenuse = cos A
cos = bĀ² - aĀ² / b
Cos is therefore equal to (bĀ² - aĀ²)/b.
5. If cos (Ī± + Ī²) = 0, then sin (Ī± ā Ī²) can be reduced to
(A) cos Ī² (B) cos 2Ī² (C) sin Ī± (D) sin 2Ī±
Explanation:
Since cos(a+Ī²) = 0,
We must determine the cost of sin (a- Ī²).
According to the trigonometric ratios, cos(a+Ī²) = 0 (a +Ī²) = cos-1(0)
At 90Ā°, cos is zero.
So, (Ī± + Ī²) = 90Ā°
Now, Ī± = 90Ā° - Ī²
Change the value of, and you get sin( - ) = sin(90Ā° -Ī² -Ī² ) = sin(90Ā° - 2Ī²).
Sin (90Ā° - A) = cos A is the trigonometric ratio of complementary angles.
Sin (90Ā° - 2Ī²) = cos (2), then.
As a result, sin (90-A) = cos 2.
6. The value of (tan1Ā° tan2Ā° tan3Ā° ... tan89Ā°) is
(A) 0 (B) 1 (C) 2 (D) Ā½
Explanation:
The ratio of (tan1Ā°, tan2Ā°, tan3Ā°,... tan89Ā°) must be determined.
Tan (90Ā° - A) = cot A is a trigonometric ratio of complement angles.
You can write the formula as (tan1Ā°, tan2Ā°, tan3Ā°,... tan 44Ā°). Tan 45 degrees (tan(90Ā°- 44Ā°)) tan(90Ā°- 43Ā°) Tan (90Ā°- 42Ā°) = (tan1Ā°, tan2Ā°, tan3Ā°,... tan 44Ā°) Tan (90Ā°- 1Ā°) Tan 45Ā° (cot 44Ā°, cot 43Ā°, cot 42Ā°, cot 41Ā°, cot 1Ā°)
We are aware that tan cot 1
Thus, (tan1Ā°x cot1Ā°) (tan2Ā° xcot2Ā°) (tan3Ā° xcot3Ā°) tan 45Ā°..........(tan44Ā° xcot44Ā°) = 1 1 1 ................. 1 = 1
The value of (tan1Ā°, tan2Ā°, tan3Ā°,..., tan89Ā°) is therefore 1.
7. If cos 9Ī± = sinĪ± and 9Ī± < 90Ā° , then the value of tan5Ī± is
(A) ā (B) 3 (C) 1 (D) 0
Explanation:
Provided that sin = cos
Given, 9Ī± < 90Ā°
The value of tan5 must be determined.
9 is an acute angle because it is 90 degrees.
Sin (90Ā° - A) = cos A is a trigonometric ratio of complementary angles.
Cos 9 = sin(90Ā° - 9), then.
Consequently, sin(90Ā° - 9) = sin 90Ā° - 9 =
When simplified, + 9 = 90Ā°
10Ī± = 90Ā°
Ī± = 90Ā°/10 Ī± = 9Ā°
To locate tan5
Change the value to provide tan 5 = tan(5 9) = tan 45Ā°.
Tan 45Ā° = 1 using the trigonometric ratio of angles.
8. If āABC is right-angled at C, then the value of cos (A+B) is
(A) 0 (B) 1 (C) Ā½ D) 3/2
Explanation:
because angle C is 90 degrees and ABC is right-angled
thus,
A+B=180-C
A+B=180-90
A+B=90
Consequently, cos(A+B)=cos90. =0
9. If sinA + sin2 A = 1, then the value of the expression (cos2 A + cos4 A) is
(A) 1 (B) Ā½ (C) 2 (D) 3
Explanation:
SinA + Sin2 A = 1 given
Sin A = 1 - sin2 A can be used to represent it. First, we need to calculate the value of (cos2 A + cos4 A).
Cos2 A = 1 - Sin2 A is the trigonometric identity that is used. (2) The second equation is sin A = cos2 A.
The result is that (cos2 A + cos4 A) = (cos2 A + (sin A)2) = cos2 A + sin2 A.
Cos2 + Sin2 = 1 using the trigonometric identities.
(Cos2 A + Cos4 A) = 1 as a result.
10. Given that sinĪ± = 1 /2 and cosĪ² = 1/2 , then the value of (Ī± + Ī²) is
(A) 0Ā° (B) 30Ā° (C) 60Ā° (D) 90Ā°
Explanation:
Because sinĪ± and cosĪ² are both halves,
We must determine the value of ( +Ī² ).
The trigonometric ratios of angles can be used to:
Given that sinĪ± = /
Ī± = sinā»Ā¹(1/2)
Ī± = 30Ā°
Given that cosĪ² = 1/2 = cosĪ² 1(1/2) = 60 degrees
Now, (Ī± + Ī²) = 30Ā° + 60Ā° = 90Ā°
As a result, the value of ( a+Ī² ) equals 90Ā°.
11. The value of the expression (sin222ā+sin268ācos222ā+cos268ā+sin263ā+cos63ā27ā) is
(A) 3 (B) 2 (C) 1 (D) 0
Explanation:
The solution is (B).
With that expression, sin222ā+sin268ācos222ā/cos268ā+sin263ā+cos63ā sin27ā=sin222ā/sin2(90āā22ā)cos2(90āā68ā)+cos268ā+sin263ā+cos63āsin27ā=sin222ā+cos222āsin268ā+co268ā+sin263ā+cos63ācos63ā[cos(90)=sin and sin(90)=cos] = 11 + (sin263+cos263) [āµsin2Īø+cos2Īø=1]=1+1=2.
12. If 4 tanĪø = 3, then 4sin cos /4sin cos is equal to
(A) ā (B)ā (c ) Ā½ (D)Ā¾
Explanation:
Considering that 4 tanĪø=3,
Finding the value of (4sinĪø - cosĪø)/(4sinĪø + cosĪø) is necessary.
So, tan = 3/4 now.
As we now know, tan A = opposite/adjacent
Contrary = 3
Adjoining = 4
(Hypotenuse) Using the Pythagorean Theorem2 = (contrary)2 + (nearby)Ā² (hypotenuse)Ā² = (3)Ā² + (4)Ā² (hypotenuse)(Hypotenuse) 2 = 9 + 16Ā² = 25
Hypotenuse equals 5 after taking the square root.
Knowing that sin A equals the reverse and hypotenuse
So, sinĪø = 3/5
We are aware that adjacent/hypotenuse = cos A
So, cosĪø = 4/5
This means that (4sinĪø - cosĪø) = 4(3/5) - (4/5) = 12/5 - 4/5 = (12 - 4)/5 = 8/5.
Now, (4sinĪø + cosĪø) = 4(3/5) + (4/5) = 12 + 4/5 = 16
Thus, (8/5) / (16/5) = 8(5) / 16(5) = 8/16 = 1/2 (4sinĪø - cosĪø)/(4sin Īø+ cosĪø).
13. If sinĪø ā cosĪø = 0, then the value of (sin4 Īø + cos4 Īø) is (A) 1 (B) Ā¾ Ā© Ā½ (D) Ā¼
Explanation:
With sinĪø(-cosĪø) = 0
We must determine the value of sin4 + cos4, where sin = cos.
As we are aware, sinĪø A/cosĪø A = tanĪø A.
Cos/Sin = TanĪø
Thus, tanĪø ā»Ā¹= 1 = tan 1(1).
tan Īø45Ā° = 1
So, Īø = 45Ā°
So, sinā“Īø = sinā“Īø 45Ā° now.
According to the table above, sin 45Ā° = 1/2.
So, sinā“ 45Ā° = (1/ā2)ā“ = 1/4
Cosā“Īø = cosā“Īø 45Ā° now.
From the table above, cos 45Ā° equals 1/2.
So, cosā“ 45Ā° = (1/ā2)ā“ = 1/4
cos4Īø + sinā“Īø = 1/4 + 1/4 = (1 + 1)/4 = 2/4 = 1/2
As a result, sinā“ + cosā“ = 1/2.
14. sin (45Ā° + Īø) ā cos (45Ā° ā Īø) is equal to (A) 2cosĪø (B) 0 (C) 2sinĪø (D) 1
Explanation:
The value of sin (45Ā° + Īø ) must be determined. - cos (45Ā° - Īø)
cos (90Ā° - A) = sin is the trigonometric ratio of the complementary angles. Cos (90Ā° - (45Ā° - Īø)) = A cos (45Ā° - Īø )
= sin(45Ā°+ Īø ) = cos(90Ā° - 45Ā° + Īø)
Cos(45Ā°- Īø) - Sin(45Ā°+ Īø) = Sin(45Ā°+ Īø) - Sin(45Ā°+ Īø) = 0.
Consequently, the supplied expression has a value of 0.
15. A pole 6 m high casts a shadow 2 3 m long on the ground, then the Sunās elevation is
(A\) 60Ā° (B) 45Ā° (C) 30Ā° (D) 90Ā°
Explanation:
Since the pole's length is 6 meters,
A 2 to 3-m-long shadow is created on the ground by the pole.
The elevation of the sun must be determined.
Let the elevation angle be.
The figure shows,
tan = opposite/hypotenuse tan = 6/2ā3 tan = 3/ā3 tan = 3 tan = opposite/hypotenuse tan = adjacent tan = 2ā3 m
Tan 60Ā° = 3 using the trigonometric ratios of angles.
So, Īø = 60Ā°
Consequently, the elevation angle is 60Ā°.
16. tan 47 /cot 43 =1
Explanation:
Assuming, tan 47Ā°/cot 43Ā°= 1,
The validity of the relationship mentioned above must be established.
Tan (90Ā° - A) = cot is the trigonometric ratio of complementary angles. A tan 47Ā° is equal to tan (90Ā° - 43Ā°) = cot 43Ā°.
In other words, tan 47Ā°/cot 43Ā° = cot 43Ā°/cot 43Ā° = 1.
Because of this, tan 47Ā°/cot 43Ā° = 1.
17. The value of the expression (cos2 23Ā° ā sin2 67Ā°) is positive.
Explanation:
The formula is cosĀ² 23Ā° - sinĀ² 67Ā°.
Whether (cosĀ² 23Ā° - sinĀ² 67Ā°) is positive must be determined.
Algebraic identity yields (aĀ² - bĀ²) = (a - b)(a + b).
As a result, cosĀ² 23Ā° - sinĀ² 67Ā° equals (cos 23Ā° - sin 67Ā°)(cos 23Ā° + sin 67Ā°).
Using the trigonometric formula for the ratio of complementary angles, sin (90Ā° - A) = cos A, sin (90Ā° - 23Ā°) = cos 23Ā°, and so forth.
CosĀ² 23Ā° - SinĀ² 67Ā° = CosĀ² 23Ā° - Cos23Ā° + Cos23Ā° = (0) CosĀ² 23Ā° - Cos23Ā° = 0
Thus, cosĀ² 23Ā° - sinĀ² 67Ā° equals 0.
18. The value of the expression (sin 80Ā° ā cos 80Ā°) is negative.
Explanation:
Considering that the formula is sin 80Ā° - cos 80Ā°
Whether the expression is negative must be determined.
According to the trigonometric ratio of angles, sinĪø grows asĪø cosĪø decreases asĪø the angle increases Īø from 0Ā° to 90Ā°.
In other words, (sin 80Ā° - cos 80Ā°) equals (growing value - declining value) = positive value.
(Sin 80Ā° - Cos 80Ā°) > 0 as a result.
19. 2 2 (1ā cos ) sec tan Īø Īø= Īø
Explanation:
(1cosĀ²).secĀ²Īø =sinĀ²ĪøĆsecĀ²Īø
=sinĪøĆsecĪø
=sinĪø/cosĪø
=tanĪø
So it is true.
20. If cosA + cos2 A = 1, then sin2 A + sin4 A = 1.
Explanation:
Assume that cos A + cosĀ² A = 1.
We must demonstrate that sinĀ²A + sinā“A = 1.
SinĀ² A = 1 - cosĀ² A is the trigonometric identity.
Therefore, cos A = 1 - cosĀ² A
sinĀ² A = cos A
At this point, (sinĀ² A + sinā“ A) = (sinĀ² A + (cos A)Ā²) = sinĀ² A + cosĀ² A.
CosĀ² + SinĀ² = 1 using the trigonometric identities.
As a result, the expression (sinĀ² A + sinā“ A) has a value of 1.
21. (tan Īø + 2) (2 tan Īø + 1) = 5 tan Īø + sec2 Īø.
Explanation:
The formula is as follows: (tanĪø + 2) (2 tanĪø + 1) = 5 tanĪø + seĀ²2.Īø
We must assess whether or not the supplied expression is true.
LHS: (tan Īø + 2) (2 tan Īø + 1)
By virtue of the distributive and multiplicative properties, = 2tanĀ² Īø + tan Īø+ 4tan Īø + 2 = 2tanĀ² Īø + 5tan Īø + 2
Using the trigonometric ratio of complementary angles, 1 + tanĀ² A = secĀ² A and tanĀ² A = secĀ² A - 1 may be calculated.
In other words, 2(secĀ² Īø - 1) + 5tan + 2 = 2secĀ² Īø - 2 + 5tan + 2 = 2secĀ² Īø+ 5tan RHS = 5 tan + secĀ² Īø
RHS LHS
22. If the length of the shadow of a tower is increasing, then the angle of elevation of the sun is also increasing.
Explanation:
We must evaluate whether the length of a tower's shadow is growing in order to ascertain whether the sun's angular height is likewise growing.
If a pole with a height of 2ā3 m casts a shadow of 2 m, the sun is at an elevation of.
According to the Pythagorean Theorem, tan = opposite or adjacent, tanĪø = 2ā3/2, tanĪø = 3, and tanā»Ā¹ = (3).
We understand that tanĪø 60Ā° =2 3.
So, Īø = 60Ā°
When the shadow lengthens to 4 m, the angle of elevation becomes.
tan Īø = 2ā3/(2 + 4)
tan Īø = 2ā3/6
tan Īø = ā3/ā3
Tan ā»Ā¹= 1/ā3 equals Tan (1/ā3)
We are aware that 30Ā° tan = 1/ā3
So, Īø = 30Ā°
The two examples show emphatically that as the length of the shadow rises, the angle of elevation decreases.
23. If a man standing on a platform 3 meters above the surface of a lake observes a cloud and its reflection in the lake, then the angle of elevation of the cloud is equal to the angle of depression of its reflection.
Explanation:
Assume that a man sees a cloud and its reflection in a lake from a platform three meters above the water level.
We must determine whether the cloud's elevation angle and its reflection's deflection angle are equal.
M should represent the stance of a guy standing on a platform.
The cloud is C.
MO is the distance between the platform and the lake's surface.
MO = 3 m
Let 1 represent the elevation angle.
Let 2 be the depression's angle.
The height of the cloud's reflection is equal to (h + 3) m.
Triangular MPC
tan Īøā=CM/PM
Tan Īøā = PM/h
PM = tan/h Īøā ------------------- (1)
MPC's triangle
TanĪø = C'M / PM
Tan Īø equals (h + 3)/PM
(h + 3)/tan Īø = PM ----------------- (2)
Based on (1) and (2),
(h + 3)/tanĪøā = h/tan1
(h + 3) tanĪøā = h(tanĪøā)
Therefore, tanĪøā = h/(h + 3) tanĪøā
It is evident that 1 and 2
As a result, the angle of depression and elevation are not equal.
24. The value of 2sinĪø can be a 1/a, where a is a positive number, and a ā 1.
Explanation:
Assuming that an is a positive number, a 1.
We must establish whether 2sinĪø can be a + (1/a).
A + (1/a) / 2 is the arithmetic mean of a and 1/a.
The geometric mean of a and 1/a is equal to 1 (a (1/a)).
As a result, [a + (1/a)]/2 > 1 [a + (1/a)] > 2 where [a + (1/a)] > geometric mean
Currently, 2sinĪø > 2 sin > 1
Consequently, 2sinĪø cannot equal a + (1/a).
25. cos Īø = a b /2ab, where a and b are two distinct numbers such that ab > 0.
Explanation:
Given that ab > 0, a and b are two separate numbers.
We must determine whether cosĪø = (a2 + b2)/2ab.
Mathematical mean > Geometric Mean
As GM=ab and AM = (a + b)/2
Thus, we obtain (aĀ²+ bĀ²)/2 > aĀ²bĀ² (aĀ² + bĀ²)/2 > ab.
By cross multiplying (aĀ² + bĀ²)/2ab, 1 is obtained.
Given is that cos > 1.
We are aware that cosĪø has a value between 0 and 1.
Hypotenuse/Base > 1
Hypotenuse > Base
Since cosĪø cannot have a value larger than 1, the assertion is untrue.
As a result, the assertion is untrue.
26. The angle of elevation of the top of a tower is 30Ā°. If the height of the tower is doubled, then the angle of elevation of its top will also be doubled.
Explanation:
Because a tower's top is 30Ā° above ground,
We must determine that if the tower's height is twice, its top's elevation angle will also be doubled, or Īø = 60Ā°.
Let AC represent the tower's height.
BC = x units and AC = h units.
30-degree elevation angle
Pythagorean theorem states that tan 30Ā° = AC/BC.
Tan 30Ā° = 1/3 1/ā3 = h/x can be calculated using the trigonometric ratio of angles. ------------ (1)
27. If the height of a tower and the distance of the point of observation from its foot, both, are increased by 10%, then the angle of elevation of its top remains unchanged.
Explanation:
Provided, the tower's height and the gap between its foot and the point of view are both increased by 10%.
We must ascertain whether the top's elevation angle hasn't changed.
Let AB represent the tower's height.
Let BC represent the distance between the object under observation and its foot.
Let AB equal x units and BC equal y units.
Be the elevation's angle
Tan = AB/BC and Tan = x/y in the triangle ABC. ------------------ (1)
Now, 10% more is added to x and y.
x = x + (1/10)x = (1 + 10)/10, and y = y + (1/10)y = 11y/10
Tan = (11/10)x/(11/10)y Tan = (11/10)x/(11/10)y ------------------- (2)
From (1) and (2), stay the same.
As a result, the elevation angle doesn't alter.
28. sinĪø /1+ cosĪø sin 1+ cosĪø/sinĪø =2cosecĪø
Explanation:
We've got
LHS = 1+sin/cos+ 1+sin/cos
LHS is equal to sin2+(1+cos)2/sin(1+cos)/.
LHS = sin(1+cos), sin2(1+cos), +1+2cos, + cos2.
LHS = (sin2 + cos2 )+1 + 2 cos / sin(1 + cos) [sin2 + cos2 = 1]
LHS = 2+2cosec/sin(1+cos) = 2(1+cos)/sin(1+cos) = 2(1+cos)/sin(1+cos) = 2cosec=RHS.
29 . tan A/1 secA ā = + ā tan A/ 1 secA 2cosec A
Explanation:
tanA/1+secA-tanA/1sec A=2ā cosecA
L.H.S]
tanA/1+sec A-tanA/1-sec A
=tanA(1āsecA)ātanA(1+secA)/1-sec 2A
=tanA(1āsecAā1āsecA)/tan 2 A
=ā2secA/-tanA
=2ā 1/cosA/sinA/cosA
=2/sinA
=2ā cosecA
=R.H.S
ā“ L.H.S=R.H.S.
30. (sin Ī± + cos Ī±) (tan Ī± + cot Ī±) = sec Ī± + cosec Ī±
LHS is equal to (sin Ī±+ cosĪ±) (tan Ī±+ cotĪ±).
We are aware that tan = sinĪ±/cosĪ± and cotĪ± = cosĪ±/sinĪ± = sinĪ± + cosĪ±. (cos/sin plus sin/cos)
By using the formula LCM = (sinĪ± + cosĪ±) [(sin2 Ī±- cos2Ī± )/cosĪ± - cosĪ±]
Due to the fact that sin2 + cos2 = 1 = (sin + cos)/cos sin
You may write it as = 1/cos + 1/sin.
In this case, 1/cosĪ± = sec Ī± and 1/sin Ī±= cosec Ī± = secĪ± + cosec Ī±= RHS.
It has therefore been proven.
31. ( 3 1+ ) (3 ā cot 30Ā°) = tan3 60Ā° ā 2 sin 60Ā°
Explanation:
LHS is equal to (ā3 + 1) (cot 30Ā°)
We are aware that 30Ā° cot = ā3 = (3 + 1) (3 - ā3)
Writen as (ā3 - 3), = ā3 (ā3 - 1) = (ā3 + 1) ā3 (ā3 - 1)
Making use of the algebraic formula (3 + 1)(3 - 1) = ((3)2 - 1)]
= ((ā3)2 - 1) ā3 = (3 - 1) ā3 = 2ā3
RHS = tan3 60Ā° - 2 sin 60Ā° should be solved.
Due to the fact that tan 600 = 3 and sin 600 = 3/2, we have (3)3 - 2.(ā3/2) = 3ā3 - ā3 = 2ā3
Thus, it is established that LHS equals RHS.
32. 1+cot2 Ī±1+cosec Ī±=cosec Ī±
Explanation:
LHS is equal to 1 + cot2 Ī± / (1 + cosecĪ±)
We are aware that cot 2 Ī±= cosec2 Ī± - 1.
LHS then equals 1 + (cosec2 Ī± - 1)/ (1 + cosecĪ±).
With the help of the algebraic formula a2 - b2 = (a + b) (a - b),
LHS is equal to 1 plus [(cosec Ī±+ 1) (cosec Ī±- 1)/ (1 + cosec Ī± )]
RHS = 1 + cosec Ī±- 1 = cosec Ī±
It has therefore been proven.
33. tan Īø + tan (90Ā° ā Īø) = sec Īø sec (90Ā° ā Īø)
Explanation:
We understand that tan (90Ā° - Īø) = cot Īø
LHS = Tan Īø(90Ā° - Tan) = Tan (Tan) + CotĪø
We are aware that tan = sin/cos and cot = cos/sin.
LHS is equal to sinĪø/cosĪø + cosĪø/sinĪø.
Using the formula LCM = (sin2Īø + cos2Īø ) / sin ĪøcosĪø
Since sin2Īø + cos2 Īø= 1 = 1/sin2Īø + cos2Īø,
It can be expressed mathematically as = 1/ cosĪø x 1/ sinĪø = sec cosec.
In this instance, cosec = sec (90Ā° - ) = sec and sec (90Ā° - ) = RHS.
It has therefore been proven.
34. Find the angle of elevation of the sun when the shadow of a pole h meters high is 3 h meters long.
Explanation:
We understand that tan (90Ā° - Īø) = cotĪø
LHS = Tan (90Ā° - Tan) = TanĪø (TanĪø) + CotĪø
We are aware that tanĪø = sinĪø/cosĪø and cotĪø = cosĪø/sinĪø.
LHS is equal to sinĪø/cosĪø + cosĪø/sinĪø.
Using the formula LCM = (sin2 + cos2 ) / sin cos
Since sin2Īø + cos2 Īø= 1 = 1/sin2 Īø+ cos2Īø,
It can be expressed mathematically as = 1/ cos Īøx 1/ sin Īø= secĪø cosecĪø.
In this instance, cosec Īø= sec Īø(90Ā° - ) = secĪø and sec (90Ā° -Īø ) = RHS.
It has therefore been proven.
35. 9. If 3 tan Īø = 1, then find the value of sin2-Īø ā cos2 Īø.
Explanation:
It is assumed that 3 tanĪø = 1.
You can write it as tan Īø= 1/3
By using the tan inverse, we get 30Ā° = tan-1 (1/3)
In order to calculate sin2 - cos2,
Let's replace sin2 30Ā° - cos2 30Ā° = (1/2) with its value.2 - (ā3/2)2
By simplifying even further, 1/4 to 3/4
We thus have = -2/4 = -1/2.
Therefore, sin2 - cos2 has a value of -1/2.
As a result, the Sun is elevated at a 30Ā° angle.
36. A ladder 15 meters long just reaches the top of a vertical wall. If the ladder makes an angle of 60Ā° with the wall, find the height of the wall.
Explanation:
Think about the ladder's length, which is 15 meters (Hypotenuse).
based on the figure
Angle between ladder and ground: <CAB = 90Ā° - 60Ā° = 30Ā° Angle between ladder and wall: <BCA = 60Ā°
We are aware that BC is equal to the height of the wall sin 30Ā°, which is BC/15 1/2.
The result is BC = 15/2 BC = 7.5 m.
Consequently, the wall is 7.5 meters tall.
37. Simplify (1 + tan2 Īø) (1 ā sinĪø) (1 + sinĪø)
Explanation:
Given are (1 + tan2Īø ) (1 - sinĪø ) and (1 + sinĪø )
Since 1 + tan2 Īø= sec2Īø,
Thus, it can be expressed as = sec2ĪøĪø (1 - sinĪø) (1 + sinĪø).
We obtain = sec2Īø (1 - sin2Īø ) by applying the algebraic identity a2 - b2 = (a + b) (a - b).
We are aware that 1 - sin2Īø = cos2Īø
By changing it to it = sec2 Īøcos2Īø
In this case, cos2 = 1/sec2Īø
Thus, we obtain = sec2 Īø1/sec2 Īø = 1
As a result, by simplifying, we obtain 1.
38. If 2sin2 Īø ā cos2 Īø = 2, then find the value of Īø.
Explanation:
The formula 2 sin2 Īø- cos2 Īø= 2 is known.
Because sin2 Īø+ cos2 Īøequals 1,
We obtain sin2Īø - (1 - sin2Īø ) = 2 sin2 Īø= co2Īø = 1 - sin2Īø = 2
Simplifying even further, 2 sin2 Īø- 1 + sin2 Īø- = 2
3 sin2 Īø = 3
Multiply both sides by 3 sin2 to get 1.
Sin = 1 after applying square roots to both sides.
Thus, we have = sinĪø-1 (1) = 90Ā°.
As a result, has a value of 90Ā°.
39. Show that 2 2 cos (45 ) cos (45 ā ) /tan (60 ) tan (30 ) =1
Explanation:
LHS = [cos2 (45Ā° +Īø ) + cos2 (45Ā° - Īø)] is an example.[sunny (60Ā° + Īø) sunny (30Ā° - Īø)]
As we are aware, cos A = sin (90Ā° - A).
(90Ā° - A) = tan A
Tan A = Cot A
We get = [cos2 (45Ā° + Īø) + sin2 (90Ā° - 45Ā° +Īø )] by swapping it.[Cotton (90Ā° - 30Ā° + Īø) in tan (60Ā° + Īø)]
Consequently, we have [cos2 (45Ā° +Īø ) + sin2 (45Ā° +Īø )].[Cotton (60Ā° + Īø) in a tan shade]
In this case, cos2A + sin2A = 1, and tanA cotA = 1.
By changing it to = 1/1 = 1.
40. An observer 1.5 metres tall is 20.5 metres away from a tower 22 metres high. Determine the angle of elevation of the top of the tower from the eye of the observer.
Explanation:
Given that the observer is 1.5 inches tall
AE=22ā1.5=20.5
In ā³AED
tanĪø=EDAEā=20.520.5ā=1āĪø=45o
41. Show that tan4 Īø + tan2 Īø = sec4 Īø ā sec2 Īø
Explanation:
LHS equals tan4Īø plus tan2Īø.
removing tan2 Īøas common results in tan2 Īø(tan2 Īø+ 1).
We are aware that tan2Īø = sec2 Īø- 1 and therefore 1 + tan2 Īø= sec2Īø.
It is possible to write it as = (sec2 Īø- 1) sec2Īø.
Thus, we obtain sec4 Īø- sec2 Īø= RHS.
It has therefore been proven.
42. If cosecĪø + cotĪø = p, then prove that cosĪø = p2-1/p2+1
Explanation:
CosecĪø + CotĪø = p given -------- (1)
It must be demonstrated that cos = p2 - 1 / 22 + 1
Trigonometric identities show that cot2 A + 1 = cose22 A.
Therefore, cosec 2 A - cot2 A = 1.
The equation (a2 - b2) can be written as (a + b)(a - b) (cosecĪø - cotĪø )(cosec Īø+ cotĪø ) = 1 (cosecĪø - cotĪø )(P) = 1 cosec Īø- cotĪø = 1/P. ---------------------- (2)
CosecĪø - cot Īø+ cosecĪø + cotĪø equals P + 1/P after adding (1) and (2).
P plus 1/P + 2cosecĪø
(P + 1/P)/2 cosecĪø
When (1) and (2) are subtracted, cosecĪø + cotĪø - cosec Īø+ cotĪø = P - 1/P.
2cot Īø = (P - 1/P)
cot Īø = (P - 1/P)/2 -------------------------- (3)
Coefficient / cosec is equal to (P - 1/P) / (P + 1/P) when (3) is divided by (2).
As we are aware, cotĪø A = cosĪø A/sinĪø A.
Additionally, cosecĪø A = 1/sinĪø A
Now, cot Īø/ cosec Īø= (cosĪø / sinĪø) / (1/sinĪø) = (cosĪø / sinĪø) (sinĪø / cosĪø)
Thus, cosĪø = (P.(P2 - 1)/(P2 + 1) = (P2 - 1)/(P2 + 1) = (P2 - 1)/(P2 + 1)
Consequently, cos = (P2 - 1)/(P2 + 1).
43. Prove that 2 2 sec cosec tan cot Īø+ Īø = Īø + Īø
Explanation:
The trigonometric identities sec2Īø=tan22+1 and cosec2Īø=cot2Īø+1 are used.
These are obtained by adding them together: sec2Īø+cosec2Īø=tan2Īø+cot2Īø+2 sec2Īø+cosec2Īø=tan2Īø+cot2Īø+2 tanĪø+cotĪø=(tanĪø+cotĪø)2 sec2Īø+cosec2Īø=tanĪø+cotĪø
Thusly Proven.
44. The angle of elevation of the top of a tower from a certain point is 30Ā°. If the observer moves 20 meters toward the tower, the angle of elevation of the top increases by 15Ā°. Find the height of the tower.
Explanation:
Because a tower's top is 30 degrees higher than a particular point,
The angle of elevation of the top increases by 15Ā° as the spectator approaches the tower by 20 m. We must determine the height of the tower.
Let D be the observation point, AB be the tower, and BCA equal 30 degrees.
Assuming CD = 20 m
The angle of elevation rises by 15Ā° as the viewer advances from point C to point D.
BDA is therefore 30Ā° + 15Ā° + 45Ā°.
Triangle BAD has
Python's Theorem states that tan 45Ā° = AB/AD 1 = h/AD
AD = h ----------------- (1)
triangular BAC
Pythagorean theorem states that tan 30Ā° = AB/AC.
1/ā3 = h/AC
As we are aware, AC = CD + AD AC = 20 + h
Now, 1/ā3 = h/(20 + h)
20 + h = 3(h) on cross multiplication
When calculated simply, 3h - h = 20 h(3 - 1) = 20 h(1.732 - 1) = 20 h(0.732) = 20 h = 20/0.732 h = 27.3 m
Consequently, the tower has a height of 27.3 m.
45. If 1 + sin2 Īø = 3sinĪø cosĪø , then prove that tanĪø = 1 or Ā½
Explanation:
Provided, Sin2 Īø+ 1 = 3sin2 Īø+ cos2Īø
It must be demonstrated that tanĪø equals 1 or 1/2.
When both sides are divided by sin2Īø, the result is 1/sin2 Īø+ sin2Īø/sin2Īø = 3sinĪø cosĪø/sin2Īø.
1/sin2Īø + 1 equals 3cosĪø/sinĪø.
As we are aware, cosecĪø A = 1/sinĪø A
Additionally, sin ĪøA/cosĪø A = cot ĪøA cosecĪø2 + 1 = 3cotĪø ------------ (1)
Trigonometric identity reveals that cot2 ĪøA + 1 = cosec2 ĪøA.
3cot Īø= cot2 Īø+ 1 + 1
3cot2 Īø- 2cot2Īø = 0
If cotĪø = x,
So, x2 - 3x + 2 = 0
Factoring reveals that x2 - x - 2x + 2 = 0 x(x - 1) - 2(x - 1) = 0 (x - 1)(x - 2) = 0
Now, x - 1 = 0 x = 1
Also, x = 2 and x - 2 = 0.
Cot now equals 1, 2
We are aware that tanĪø = 1/cotĪø.
Tan then equals 1/1 or 1/2.
Tan thus equals 1 or 1/2.
46. Given that sinĪø + 2cosĪø = 1, then prove that 2sinĪø ā cosĪø = 2.
Explanation:
Provided that sinĪø + cosĪø 2 = 1,
It must be demonstrated that 2sinĪø - cosĪø = 2.
Putting a square on both sides, (sinĪø + 2cosĪø)Ā² = 1
(A + B)Ā² = AĀ²+ 2AB + BĀ² is an algebraic identity.
Therefore, (sinĪø + 2cosĪø)2 is equal to sinĀ² Īø+ 4sinĀ² Īø+ 4cosĀ²Īø
Therefore, sinĀ² Īø+ 4sin Īø+ cosĀ² Īø= 1.
Trigonometric identity reveals that cosĀ²Īø A = 1 - sinĀ² ĪøA and sinĀ² ĪøA = 1 - cosĀ² ĪøA.
As a result, (1 - cosĀ² Īø) + 4 cosĪø + 4 (1 - sinĀ²Īø ) = 1
1 + cosĀ²Īø + 4 + 4sinĀ²Īø + 4 sinĪø cosĪø = 1 5 + cosĀ² Īø+ 4 + 4sinĪø cosĪø = 1
Rearranging results in 5 - 1 = cosĀ²Īø + 4sinĀ²Īø - 4 sinĪø cosĪø, where cosĀ² Īø+ 4sinĀ² Īø- 4sinĪø cos equals 4. --------------- (1) The algebraic identity (a - b)Ā² = aĀ² - 2ab + bĀ² can be found. --------------------- (2) When comparing (1) and (2), we see that aĀ²= 4sinĀ²Īø a = 2sin Ā²ab = 4sin cos ab = 2sinĪø cosĪø.
bĀ² = cosĀ²Īø.
47. The angle of elevation of the top of a tower from two points distant s and t from its
foot are complementary. Prove that the height of the tower is S and T.
Explanation:
Because the two points s and t are spaced apart from the base of a tower, the angle of elevation at the tower's top is complimentary.
We must provide evidence that the tower is āst in height.
Make AC represent the tower's height.
units of AC = h
The places of observation are P and B.
If PC = t units and BC = s units, then
Given that ABC = APC = 90Ā° -, the angle of elevation is complimentary.
Tan Īø = AC/BC in triangle ABC
tan Īø = h/s ------------------ (1)
Tan Īø (90Ā°- ) = AC/PC in the triangle APC
Tan Īø(90Ā° - A) = cot Īø A is the result of the trigonometric ratio of complementary angles.
Consequently, tan (90Ā°-) = cot Īø = cot Īø= AC/PC
cot Īø = h/t -------------------- (2)
Sun Īø = cot Īø= (h/s)(h/t) is obtained by multiplying (1) and (2).
We are aware that tan cot 1
Thus, 1 = h2/st and h2 = st
Using square root, h equals st.
The tower's height is thus st.
48. The shadow of a tower standing on a level plane is found to be 50 m longer when
Sunās elevation is 30Ā° than when it is 60Ā°. Find the height of the tower.
Explanation:
Because the length of a tower's shadow on a level plane is determined to be 50 m longer at 30Ā° elevation than at 60Ā°, we must determine the tower's height.
Let SQ represent the tower's height.
SQ = h m
The initial angle of elevation: ā SRQ = 60Ā°
The shadow's initial length is equal to x meters.
When the angle of elevation ā SPQ = 30Ā°, the shadow of the tower is extended by 50 meters.
Tan 60Ā° in the triangle ā SRQ equals SQ/RQ 3 = h/x x = h/3 m. --------------- (1)
Tan 30Ā° = SQ/PQ in the triangle SPQ
PQ = PR + RQ, which means that PQ = 50 + x 1/3 = h/(50+x).
When multiplying by themselves, 50 + x = 3h x = 3h - 50. ------------ (2)
According to (1) and (2), h/3 = 3h - 50
According to grouping, h/3 - 3h = -50 3h - h/3 = 50
If you simplify, (3h-h)/3 equals 50.
2h/ā3 = 50
2h = 50ā3 h = 50ā3/2 h = 25ā3 m
As a result, the tower has a height of 25 3 m.
49. A vertical tower stands on a horizontal plane and is surmounted by a vertical flagstaff of height h. At a point on the plane, the angles of elevation of the bottom and the top of the flagstaff are Ī± and Ī², respectively. Prove the height of the tower.
Explanation:
Provided, a vertical tower rests on a horizontal plane and is topped by an h-foot-tall vertical flagstaff.
The flag staff's bottom and top are elevated at an angle of and, respectively.
We must demonstrate that the tower is [h tan]/(tan - tan)].
Let PO represent the vertical tower and FP represent the flagstaff.
Given the vertical staff's height, FP = h units
Let the tower's height be in H units.
The angle of depression, ā FRO = źµ
ā PRO = āŗAngle of elevation
Let RO be the distance in units between the observation point and the tower's base.
Tan = PO/RO in triangle PRO
H/x x = H/tan = tan āŗ------------------- (1)
Tanāŗ = FO/RO for the triangle FRO
The figure shows that FO = FP + PO.
FO = h + H
Thus, x = (h + H)/tan = tan = (h + H)/x. ----------------- (2)
According to (1) and (2), H/tanāŗ = (h + H)/tan
When cross-multiplied, H(tan ) equals (h+H) tan.
H(tanźµ ) equals H(tanźµ ) plus h(tanźµ ).
In order to find H, we get H(tan źµ) - H(tanźµ ) = h(tan źµ).
Tanźµ - Tanźµ = H(tan āŗ- Tanāŗ)
H is equal to h(tan źµ ) / (tanźµ - tanźµ ).
As a result, the tower's height is [h tanāŗ]/(tan źµ - tanāŗ)].
50. If tanĪø + secĪø = l, then prove that secĪø = l 2+1/2l
Explanation:
It is known that tan Īø+ secĪø = l ------------------- (1)
We must demonstrate that secĪø = lĀ²+ 1/2l.
Thinking about LHS: tanĪø + secĪø
Using the operations (sec Īø- tanĪø), (tanĪø + secĪø)(secĪø - tanĪø)/(secĪø - tanĪø), multiply and divide the numbers
Algebraic identity yields (aĀ² - bĀ²) = (a - b)(a + b).
As a result, (tanĪø + secĪø)(sec Īø- tanĪø) = (secĀ²Īø - tanĀ²Īø)
LHS is now equal to (secĀ²Īø - tanĀ²Īø) / (secĪø - tanĪø).
Trigonometric identity demonstrates that 1 + tanĀ²Īø A = secĀ²Īø A.
When arranged, secĀ² ĪøA - tan ĪøA equals 1.
This means that (secĀ² Īø- tanĀ² Īø) / (sec Īø- tanĪø) = 1/(sec Īø- tanĪø)
The result is now 1/(secĪø - tanĪø) = l (sec Īø- tanĪø) = 1/l. ---------------------- (2)
When (1) and (2) are combined, (tanĪø + secĪø) + (secĪø - tanĪø) = l + 1/l.
2secĪø = l + 1/l
In a simplified formula, 2secĪø = (lĀ² + 1)/l secĪø
Consequently, secĪø = lĀ² + 1/2l.
51. If sinĪø + cosĪø = p and secĪø + cosecĪø = q, then prove that q (p2 ā 1) = 2p.
Explanation:
Assuming that sinĪø + cosĪø = p and secĪø + cosecĪø = q.
It must be demonstrated that q (p2 - 1) = 2p.
Regarding LHS: q (pĀ² - 1)
When p and q are substituted, the result is (sec Īø+ cosecĪø)[(sin Īø+ cosĪø)2 - 1].
Algebraic identity reveals that (a + b)2 = a2 + 2ab + b2 (sinĪø + cosĪø)Ā² is equal to sinĀ² Īø+ 2sinĪø cosĪø + cosĀ²Īø.
Using the trigonometric identity, cosĀ² ĪøA plus sinĀ²Īø A equals one.
Consequently, sinĀ² Īø+ 2sinĪø cosĪø + cosĀ² Īø= 1 + 2sinĪø cosĪø.
[(sin Īø+ cosĪø)Ā² - 1] now equals 1 + 2 sinĪø cosĪø - 1 = 2 sinĪø cosĪø.
At this point, (sec Īø+ cosecĪø)[(sinĪø + cosĪø)Ā² - 1] = (secĪø + cosecĪø)(2sin ĪøcosĪø) is the result.
We are aware that sec Īø= 1/cosĪø A and cosecĪø = 1/sinĪø A are equivalent to (1/cosĪø + 1/sinĪø)(2sinĪø cosĪø).
With regard to simplification, = [(sinĪø + cosĪø)/sinĪø cosĪø](2sinĪø + cosĪø) = 2(p + sinĪø + cosĪø) = RHS
RHS LHS
Consequently, q (pĀ² - 1) = 2p.
52. If a sinĪø + b cosĪø = c, then prove that a cosĪø ā b sinĪø = 222 abc + ā .
Explanation:
\asinĪ¦+bcosĪ¦=c
balancing the two sides
A2sin2 + B2cos2 + 2absin2 cos = C2
aĀ²(1-cosĀ²Ī¦)+bĀ²(1-sinĀ²Ī¦)+2absinĪ¦cosĪ¦=cĀ²
aĀ²-aĀ²cosĀ²Ī¦+bĀ²-bĀ²sinĀ²Ī¦+2abcosĪ¦sinĪ¦=cĀ²
aĀ²+bĀ²-cĀ²=(acosĪ¦-bsinĪ¦)Ā².
53. Prove that 1 sec ā tan /+ Īø+ Īø = 1 āsinĪø /cosĪø
Explanation:
L.H.S=
1+secĪøātanĪø/ 1+secĪø+tanĪø
= secĪøātanĪø+1/ secĪø+tanĪø+1
= secĪøātanĪø+(secĪø+tan2 Īø)/sec Īø+tan Īø+1 [sec2ĪøātanĪø=1]
= secĪøātanĪø+(secĪøātanĪø)(secĪø+tanĪø)/sec Īø+tan Īø+1
= (secĪøātanĪø)(1+secĪø+tanĪø)/1+secĪø+tanĪø
=1/cosĪø-sinĪø/cosĪø
=1-sinĪø/cosĪø=R.H.S
So it was confirmed.
54. The angle of elevation of the top of a tower 30 m high from the foot of another tower in the same plane is 60Ā° and the angle of elevation of the top of the second tower from the foot of the first tower is 30Ā°. Find the distance between the two towers and also the height of the other tower.
Explanation:
Because a tower's top is 30 meters high and its base is 60 degrees from another structure in the same plane,
The top of the second tower is 30Ā° higher than the bottom of the first tower.
We must determine the separation between the two towers as well as the second tower's height.
With a height of 30 m and an angle of elevation of <QAB = 60Ā°, let BQ be the first tower.
PA should be the second tower, standing at h m.
The separation between the two towers is given by the angle of elevation, <PBA = 30Ā° AB.
Triangular AQB
Pythagorean theorem states that tan 60Ā° = QB/AB.
Tan 60Ā° = 3 using the trigonometric ratio of angles
Consequently, 3 = 30/AB AB = 30/3 m AB = 3(10)/AB AB = 103 m
As a result, there are 103 meters between each tower.
Pythagorean theorem: Tan 30Ā° = AP/AB for triangle APB
Tan 30Ā° = 1/3 using the trigonometric ratio of angles
The result is that 1/3 = AP/(30/ā3) AP = (30/ā3)/3 AP = 30/ā3 AP = 10 m.
Consequently, the second tower has a 10 m height.
55. From the top of a tower h m high, the angles of depression of two objects, which are in line with the foot of the tower are Ī± and Ī² (Ī² > Ī±). Find the distance between the two objects.
Explanation:
The angles of depression of two objects that are parallel to the tower's foot are provided as and Ī² (Ī² > ), and we must determine their distances from the tower's top.
Make AB the tower.
The tower is h meters tall.
The angle of depression, <ABD = š¼
< ACD = Ī² Angle of depression.
Think about BC = x CD = y.
We can infer that a triangle's alternate angles are equal by looking at its attributes.
Therefore, ABD = <BAX = š¼
< ACD = <CAY = Ī².
Triangle ABD results in tan = AD/BD, tan = h/BC + CD, tan = h/x+y, and tan = h/tan. - x -------------------(1)
Triangle ACD results in tan = AD/CD tan = h/y y = h/tan. -----------------------(2)
As a result of comparing (1) and (2), we arrive at the following equation: h/tan - x = h/tan - h/tan x = h(1/tan - 1/tan) x = h(cot - cot)
The necessary distance is therefore h(cot - cot).
56. A ladder rests against a vertical wall at an inclination Ī± to the horizontal. Its foot is pulled away from the wall through a distance p so that its upper end slides a distance q down the wall and then the ladder makes an angle Ī² to the horizontal. Show that p/q =cosĪ²-cosĪ²/sin š¼-sinĪ²
Explanation:
Assume that a ladder is leaning horizontally against a vertical wall.
The ladder establishes Ī± an angle to the horizontal by pulling its foot away from the wall by a distance p, allowing its upper end to slide down the wall by a distance q.
It must be demonstrated that p/q = cosĪ² - cosĪ± and sinĪ± - sinĪ².
Let AB represent the ladder leaning up against the wall.
<BAO =š¼ Angle of Inclination
The upper end of the ladder slides a distance q down the wall when the foot is moved away via a distance p.
SQ is the ladder following the slide.
SA = p, the pulled-away distance
BQ = q, distance slide down the wall
QSO = Angle of Inclination
Let's think about,
QO = x and AO = y
Now consider the wall's height: BO = q + x
In light of the triangle BAO, we obtain
cos OA/AB =
y/AB = cos
If y = ABcos,
Further, OA = AB cosš¼ --------------- (1)
sin(OB, AB)
OB = BA sinš¼ ----------------------- (2)
Given triangle QSO, we obtain sin(QO/SQ)
QO = SinĪ² SQ
c0 = SO/SQ
SQcosĪ² = SO
We have AB because the ladder's length stays the same.
Since = SQ,
AB = QO sinĪ² ---------------------- (3)
AB = SO cos Ī²---------------------- (4)
As far as we are aware, SA = OS - AO p = AB cosĪ² - AB cos.
CosĪ² - Cosš¼ = p = AB ------------------- (5)
BO - QO = BQ
q = BA AB sinš¼ - sinĪ²
(sinš¼ - sinĪ²) = q ----------------------- (6)
We are required to demonstrate that p/q = cos - cosš¼/ sinš¼ - sinĪ² in order to answer the question.
p/q is equal to AB (cosĪ² - cos)/BA (sin - sinĪ²).
P/Q is equal to (cosĪ² - cos)/ (sinš¼ - sinĪ²).
Consequently, p/q = (cosĪ² - cosš¼)/ (sinš¼ - sin)Ī².
57. The angle of elevation of the top of a vertical tower from a point on the ground is 60o. From another point 10 m vertically above the first, its angle of elevation is. 45oFind the height of the tower.
Explanation:
Because a vertical tower's top is 60 degrees higher than a point on the ground,
We need to determine the tower's height since the angle of elevation is 45 degrees from a second point that is vertically above the first.
AP should act as the vertical tower.
Vertical tower height, AP = 10m
<TPO's angle of elevation is 60 degrees, while <TAB's angle of elevation is 45 degrees.
According to the diagram above, OB = AP = 10m.
Let's think about,
PO = x m, which is the distance from the observation point to the tower's base
TO = h m, or the tower's overall height
The figure shows that TB = (h - 10)m.
Taking into account the <TPO, we obtain tan60 = TO/PO.
Given that tan60Ā° = 3 3 = h/x x = h/3, ---------(1)
Taking into account the TAB, we obtain tan45Ā° = TH/AB.
45Ā° Tan = TO - TH/AB
tan45Ā° = 1, so 1 = h - 10/AB.
AB = h -10 x = h -10-----------------(2)
The result of comparing (1) and (2) is h/3 = h -10 h - h/3 = 10 h(1 - 13) = 10 h(3 - 1/3) = 10 h = 103/3 - 1
Consider conjugate, h
= 10ā3/ā3 - 1 Ć ā3 - 1/ā3 - 1
h = 30 + 10ā3/3 - 1
h = 30 + 10ā3/2
h = 15 + 5ā3
h = 5(3 + ā3)
h = 5ā3 (ā3 + 1)
The tower's height is therefore 5ā3 (3 + 1)m.
58. A window of a house is h meters above the ground. From the window, the angles of elevation and depression of the top and the bottom of another house situated on the opposite side of the lane are found to be Ī± and Ī², respectively. Prove that the height of the other house is h ( 1 + tan Ī± cot Ī² ) meters.
Explanation:
Assume that a window is h m above the ground.
From the window, it can be seen that another house on the other side of the lane has an angle of elevation and depression of the top and bottom that is Ī± and Ī²
We must provide evidence that the other house is h (1 + tan Ī± cot Ī²) meters tall.
W represents the house's window in the figure.
BW = h m, the window's height above the ground
Make OQ a different dwelling.
Height of the neighboring building, QO = Hm
Angle of depression, WOB = Angle of elevation, <QWMš¼
Think about BO = xm.
Tan = QM/WM in the triangle QWMš¼
tan = H - h/x x = H - h/tan since QM = QO - MO.--------------------(1)
Taking into account triangular WOB, tan = WB/BO
Tan = h/x x, and Tan = h/tanš¼--------------------------(2) When we compare (1) and (2), we obtain,
(H - h)/tan = (H - h)/tan Tan equals h Tan
(H - h)/tan Ī± = h/tan Ī²
(H - h) tan Ī² = h tanš¼
H tanĪ² - h tanĪ² = h tanš¼
H tanĪ² = h tanš¼ + h tanĪ²
H tanĪ² = h (tanš¼ + tanĪ² )
H = (h (tanš¼ + tanĪ²))/tanĪ²
H = h (tanš¼ /tanĪ² + 1)
H = h (1 + tanš¼ /tanĪ²)
H = h (1 + tanš¼ cotĪ²)
Consequently, the second house's height.
59. The lower window of a house is at a height of 2 m above the ground and its upper window is 4 m vertically above the lower window. In a certain instant, the angles of elevation of a balloon from these windows are observed to be 60o and 30o respectively. Find the height of the balloon above the ground.
Explanation:
Because a house's lower window is 2 meters above the ground
The higher window is 4 m above the lower window vertically.
From these windows, a balloon is observed to rise at angles of 60Ā° and 30Ā°.
We must determine the balloon's height above the ground.
W1 is the upper window in the figure.
W2 is the bottom window.
Lower window's height above the ground, OR = 2m
RQ = 4m is the distance between the top of the lower window and the upper window.
The angle at which the balloon is elevated from the lower window, <BWāR = 60Ā°
Height of the balloon from the ground, BO = h m Angle of elevation of the balloon from an upper window, <BWāR = 30Ā°
PO = xm is the distance from the point of observation to the foot.
Since tan60Ā° = 3 3 = BO - RO/PO 3 = h - 2/x x = h - 2/3 in the triangle BWāR ----------------(1)
In the triangle BWāR, tan30Ā° = BQ/W1R since W1R = PO = x x = 3(h - 6) and tan30Ā° = 1/3 1/3 = h - 6/x------------------------(2) When we compare (1) and (2), we discover that h - 2/3 = 3(h - 6) h.- 2 = 3(h - 6)
h - 2 = 3h - 18
3h - h = 18 - 2
2h = 16
h = 8m.
Consequently, the balloon is 8 meters above the earth.
Chapter-8, INTRODUCTION TO TRIGONOMETRY AND ITS APPLICATIONS