Examples 6.5.2(a):
- If f(x) = x, then
=
(x - c) / (x - c) = 1 so that f'(x) = 1 for all x.
- If f(x) = 1 / x, then
=
(1/x - 1/c) / (x - c) = (c - x) / (x - c) * 1 / (x c) = - 1 / c2, so that f'(x) = - 1 / x2 for all x not equal to zero.