Find the value of 'A', if 2cos 3A = 1

Sum

2cos 3A = 1
⇒ cos 3A = `(1)/(2)`
⇒ cos 3A = cos60°
⇒ 3A = 60°
⇒ A = 20°.

shaalaa.com

Trigonometric Equation Problem and Solution

Is there an error in this question or solution?

Chapter 27: Trigonometrical Ratios of Standard Angles - Exercise 27.1

Chapter 27 Trigonometrical Ratios of Standard Angles
Exercise 27.1 | Q 4.4

Find the magnitude of angle A, if tan A - 2 cos A tan A + 2 cos A - 1 = 0

Find the value of: `sqrt((1 - sin^2 60°)/(1 + sin^2 60°)` If 3 tan²θ - 1 = 0, find the value
a. cosθ
b. sinθ

In a rectangle ABCD, AB = 20cm, ∠BAC = 60°, calculate side BC and diagonals AC and BD.

Find lengths of diagonals AC and BD. Given AB = 24 cm and ∠BAD = 60°.

In right-angled triangle ABC; ∠B = 90°. Find the magnitude of angle A, if:
a. AB is `sqrt(3)` times of BC.
B. BC is `sqrt(3)` times of BC.

Express each of the following in terms of trigonometric ratios of angles between 0° and 45°: sin53° + sec66° - sin50°

Evaluate the following: sin(35° + θ) - cos(55° - θ) - tan(42° + θ) + cot(48° - θ)

Evaluate the following: `(3sin37°)/(cos53°) - (5"cosec"39°)/(sec51°) + (4tan23° tan37° tan67° tan53°)/(cos17° cos67° "cosec"73° "cosec"23°)`

Prove the following: tanθ tan(90° - θ) = cotθ cot(90° - θ)

If A + B = 90°, prove that `(tan"A" tan"B" + tan"A" cot"B")/(sin"A" sec"B") - (sin^2"B")/(cos^2"A")` = tan²A