Respuesta :

f(pi/2) = -2cos(2pi-3) = -2cos(-3) = 2cos3

f(pi/4) = -2cos(pi-3) = -2cos(-3) = 2cos3.

So the rate of change ison the interval from x = 0 to x = pi over 4 is:

4cos3/(pi/4)=16cos3/pi