Find the area of the parallelogram... hurry

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

Find the area of the triangle shown 3 by 6

The domain of a function can be represented by which one of the following options? o a. a set of output values o b. a set of f(x) values o c. a set of input values o d. a set of both input and output values