The frequency F of a fire truck siren heard by a stationary observer is given below, where v represents the velocity of the accelerating fire truck in meters per second (see figure). (Round your answers to 3 decimal places).

F =	131,400
333 v

(a) Find the rate of change of F with respect to v when the fire truck is approaching at a velocity of 20 meters per second (use v).

(b) Find the rate of change of F with respect to v when the fire truck is moving away at a velocity of 20 meters per second (use +v).