(a) Graph the function $ f(x) = \sin x - \frac{1}{1000} \sin (1000x) $ in the viewing rectangle
$ [-2 \pi, 2 \pi] $ by $ [-4, 4] $. What slope does the graph appear to have at the origin?
(b) Zoom in to the viewing window $ [-0.4, 0.4] $ by $ [-0.25, 0.25] $ and estimate the value of $ f'(0) $. Does this agree with your answer from part (a)?
(c) Now zoom in to the viewing window $ [-0.008, 0.008] $ by $ [-0.005, 0.005] $. Do you wish to revise your estimate for $ f'(0) $?