Use a sum or difference formula to find the exact value of the trigonometric function

Simplify the algebraic expression and the corresponding trigonometric expression.

Write the given expression as a function of x.

Find the solutions to the equation in the interval 

Find all solutions of this equation:

Complete the identity

Use an identity to evaluate the expression

Find the other trigonometric functions of 

According to Timberlake, constraints on learning occur ______.

John is a baseball player. Every time he comes up to bat, he looks up at the sky, hits both shoes with his bat, hits the plate, and then stands ready. This is an example of ______.