### Home > PC3 > Chapter Ch8 > Lesson 8.3.5 > Problem 8-151

8-151.

These expressions look complicated, but they are not if you know your trigonometric identities. Review the addition/subtraction formulas, double-angle formulas, and half-angle formulas. Then simplify each of the expressions below.

Use the angle sum formula for sine.

Use the Double-Angle formula for the sine.

Use the Double-Angle formula for the cosine.

Use the angle sum formula for the cosine.

Use the Half-Angle formula for cosine.

Use the Half-Angle formula for sine.