- #1

Karol

- 1,380

- 22

## Homework Statement

## Homework Equations

At local minimum or maximum the first derivative equals zero

## The Attempt at a Solution

a) $$f'=2x-\frac{a}{x^2},~~2\cdot 2-\frac{a}{4}=0~\rightarrow a=16$$

Near 0 from the left a/x gets large negative values, smaller than for a=16. that's my proof for the local minimum.

The same for b).

But how to prove c)?

If a>0, f'<0 for x<0. so f decreases. for x>0 we found a minimum, and f''>0, so it holds water.

Similar reasoning for a<0. is this the way?