Question

If f(x) = -x^3 + x + 1/x then f'(-1) is what?

Answer 1

-3

Explanation:

f(x) = -x^3 + x + 1/x = -x^3 + x + x^-1

f'(x) = -3x^2 + 1 + -x^-2 = -3x^2 + 1 - 1/x^2

f'(-1) = -3(1) + 1 - 1/1

= -3