### Home > PC3 > Chapter 9 > Lesson 9.1.2 > Problem9-31

9-31.

Simplify each of the following trigonometric expressions.

1. $\frac{\cot(x)}{\sin(x)}(\sec(x)-\cos(x))$

1. Change all terms to sine and cosine.
2. Get a common denominator for the terms in the parentheses.
3. Use the Fundamental Pythagorean Identity.

1. $(\cos(x) + 1)(\cos(x) − 1) + \sin^2(x)$

1. Multiply out on the left side.
2. Use the Fundamental Pythagorean Identity.