How do you raise s to the 4th power

Which of the following is the true for f(x) = 5cos

Players on the school soccer team are selling candles to raise money for an upcoming trip. each player has 24 candles to sell. if a player sells 4 candles a profit of$30 is made. if he sells 12 candles a profit of $70 is made. determine an equation to model his situation?

This is about circle theorems. someone asap : (