Number 11.30 and 11.31. Please help me

missile were aimed 11.30. Calculate the difference in the apparent values of the acceleration due to gravity at the equator and the poles. Assume Earth to be spherical in shape. 11.31. Derive the familiar expression for velocity in plane polar coordinates by examining the motion of a particle in a rotating coordinate system in which the velocity is instantaneously radial. Remem- ber in an inertial coordinate system that v = rf + r00.