The voltage, V (in volts), in an electrical outlet is given as a function of time, t (in seconds), by the function V(t) = 156 cos(120πt).

(a) Find the rate of change of voltage with respect to time.

V '(t) =

ok so i found the rate of change, it is

-18720(pi)(sin(120pi(t))

now it wants to know the maximum value of the rate of change...can someone tell how to find it please..thanks

mathlete