Question

Find the derivative of f(x) = 4/x at x = 2

-4

-1

1

4

Answer 1

plug in 2

Answer 2

so its -1???

Answer 3

@primeralph

Answer 4

This is an application of the power rule.

\(f(x) = \dfrac{4}{x} = 4x^{-1}\)

Thus \(f'(x) = 4(-1)x^{-2} = -\dfrac{4}{x^{2}}\)

Evaluating, then, as \(x = 2\), gives \(f'(2) = -\dfrac{4}{(2)^{2}} = -1\)

Answer 5

yeah, you're right.

Answer 6

medal?