VERY SIMPLE PLEASE HELP DUE VERY SOON

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $36.98. find the probability that a randomly selected bill will have an amount greater than $173, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

If the figures below are similar give the scale factor of figure a to figure b