How to find net change

Question

A function is given.

f(z) = 3 − 4z²;    z = −2, z = 0

(a) Determine the net change between the given values of the variable.

(b) Determine the average rate of change between the given values of the variable.

Answer 1

f(0)=3, f(-2)=-13 ... f(-2)-f(0)=Δf=-13-3= -16 = net change of f

Δz = -2-0=-2 ... Δf/Δz=-16/-2=8 = average rate of change of f with respect to z