Math homework that I have no clue how to even approach? Help please.If a stone is thrown down at 130 ft/s from a height of 1,450 feet, its height after t seconds is given by s = 1,450 β 130t β 16t^2.(a) Find its average velocity over the period [1, 4].=___ft/s(b) Estimate its instantaneous velocity at time t = 4. =___ ft/s