Which math operation determines the following recursive sequence! 1,4,4, 16, 64, ...?
4
multiplication
addition
division
subtraction

I'm confused on this could anyone me and show me what i need to do to solve it.

Which statement about the annual percentage rate (apr) is not true?

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters