### Home > CCA2 > Chapter 12 > Lesson 12.2.3 > Problem 12-130

12-130.

Write

you can use the Angle Difference Identity.

Refer to the Math Notes in Lesson 12.2.3.

Substitute the angles into the Angle Difference Identity.

Substitute the exact values for each part of the equation.

Then simplify the multiplication and subtraction.

Repeat this process for cosine.