Question

cos 5 theta= 16 cos^5 - 20cos^3 theta + 5cos theta

Answer 1

The identities used are:

• cos (A+B) = cos A cos B - sin A sin B
• cos 2A = 2 cos^2 A - 1
• sin 2A = 2 sin A cos A
• cos 3A = 4 cos^3 A - 3 cos A
• sin 3A = 3 sin A - 4 sin^3 A
• sin^2 A = 1 - cos ^2 A

Hope it helps

Answer 2

Answer:

Step-by-step explanation:

Is below

The identities used are:

• cos (A+B) = cos A cos B - sin A sin B

• cos 2A = 2 cos^2 A - 1

• sin 2A = 2 sin A cos A

• cos 3A = 4 cos^3 A - 3 cos A

• sin 3A = 3 sin A - 4 sin^3 A

• sin^2 A = 1 - cos ^2 A