Domesticated animals contribute to the well-being of humans throughout the world, which is not a contribution?

Byproducts are:

Which is a ewe?

Which is not a method of grading wool?

Which is a stag?

Use identities to find value of 

Solve the equation for exact solutions

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

Find the solutions to the equation in the interval 

Simplify the algebraic expression and the corresponding trigonometric expression.