Approximate the derivative of y=x^3 at x=2 by assuming delta x = 0.001 and determining the corresponding change delta y. Compare the approximate value with the exact value.
This is what I did - does it look at all right?
y(2)=(2)^3=8
y(2.01)=(2.01)^3=8.120601
delta y=8.120601-8=0.120601
dy/dx~delta y/delta x = 0.120601/0.001=120.601