Trigonometry

If cos A = 4/5, find cos 2A.

What is sin(A - B) cos B + cos(A - B) sin B?

Value of sin 105° is same as:

Which of the following is equivalent to cot(A - B)?

Simplify: 4 sin³ 10° - 3 sin 10°.

Express sin 3θ in terms of sin θ.

Simplify: (cos 3A / cos A) + (sin 3A / sin A).

In triangle ABC, tan A + tan B + tan C is equal to:

Simplify: √( (1 - cos A) / (1 + cos A) ).

What is the value of cos 20° cos 40° cos 80°?

Simplify: (sin 5A - sin 3A) / (cos 5A + cos 3A).

Value of tan 22.5° is:

What is the value of sin 18°?

If tan A + tan B + tan C = tan A tan B tan C, what can be said about A + B + C?

Simplify: 2 cos(π/4 + A) cos(π/4 - A).

The value of cos² A + cos²(60+A) + cos²(60-A) is:

Simplify: (sin 3A + sin A) / (cos 3A + cos A).

Find the value of tan 15° + cot 15°.

If cos θ + sin θ = √2 cos θ, then cos θ - sin θ is:

Value of cos 36° is: