If f and g are inverse functions, what is (fog)(-1)

Find the value of the cosine for angle a

What is sin 7x/4 ? i need on this urgent trig

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?