### Home > PC3 > Chapter Ch8 > Lesson 8.2.1 > Problem8-63

8-63.

Use the Pythagorean Identity to simplify each trigonometric expression.

Review your work from problem 8-47.

1. $\cos^{2}\left(θ\right) + \sin^{2}\left(θ\right)$

1. $1-\cos^2(θ)$

1. $1-\cos^2\left(5\right)$

1. $1-\sin^2\left(β\right)$

1. $1-\sin^2\left(3δ\right)$

1. $4-4\sin^2\left(3δ\right)$

Factor out a $4$ first.