Which one is a function?

The circumference of a circle is 5 pi cm. what is the area of the circle?

A) find the derivative of the inverse to f(x) = 3x + sint at x 6. b) (cale) find the derivative of the inverse to f(x)+3sin at x 6. if x +2y -34, ind he behaviar of the cure at 4,.3), c) a. increasing, concave up d. decreasing, concave down b. increasing, concave down e. decreasing, inflection point c. decreasing, concave up

If the alternate hypothesis of an experiment is “the true mean height of the giraffes is more than 15 feet” what is the null hypothesis?