Write each function as an expression involving functions of θ or x alone. See Example 2.

sin(45° + θ)

Write each function as an expression involving functions of θ or x alone. See Example 2.

tan (π/4 + x)

Write each function as an expression involving functions of θ or x alone. See Example 2.

sin (3π/4 - x)

Write each function as an expression involving functions of θ or x alone. See Example 2.

tan(180° + θ)

Express each function as a trigonometric function of x. See Example 5.

cos 3x

Use the identities for the cosine of a sum or difference to write each expression as a trigonometric function of θ alone.

cos(270° + θ)

Express each function as a trigonometric function of x. See Example 5.

cos 4x

Find cos(s + t) and cos(s - t).

cos s = - 8/17 and cos t = - 3/5, s and t in quadrant III