Question

Write the expression as the sine, cosine, or tangent of an angle.

Answer 1

Answer:

$\sin (8x)=\sin (9x) \cos (x) - \cos (9x)\sin (x)$

Step-by-step explanation:

Given : Expression $\sin (9x) \cos (x) - \cos (9x)\sin (x)$

To write : The given expression as the sine, cosine, or tangent of an angle?

Solution :

The given expression is in the form $\sin A\cos B-\cos A \sin B$

Using trigonometric identity,

$\sin (A-B)=\sin A\cos B-\cos A \sin B$

Substituting, A=9x , B=x

$\sin (9x-x)=\sin (9x) \cos (x) - \cos (9x)\sin (x)$

$\sin (8x)=\sin (9x) \cos (x) - \cos (9x)\sin (x)$

Therefore, The given expression is in the sin form sin(8x).

Answer 2

Answer:

sin 8x

Step-by-step explanation: