Solve the problem.A consumer notes the sinusoidal nature of her monthly power bills. In winter when she uses electricity to heat her home and in summer when she cools her home, the bills are high. In spring and fall, significantly less electricity is used and the bills are much smaller. The following function models this behavior. C = 60 + 40 cos Here C is the cost of power in dollars for the month t, 1 ? t ? 12, with t = 1 corresponding to January. For what values of t, 1 ? t ? 12, is the cost exactly $80?

Question

Fill in the blank(s) with the appropriate word(s).

Answer 1

t = 0, 2, 6, 8, 12