1. ## Finding critical numbers

I am stuck on a question for my calc h.w

it reads to find the critical numbers of x^-2 ln x

When I took the derivative I got -2x^-3 lnx + x^-2 *1/x

I simplified and set it equal to zero. the critical numbers i got were 0 and e^1/2 however the question says I'm wrong

2. ## Re: Finding critical numbers

What is the domain of the function?

3. ## Re: Finding critical numbers

Originally Posted by neontiger94
it reads to find the critical numbers of x^-2 ln x
When I took the derivative I got -2x^-3 lnx + x^-2 *1/x
I simplified and set it equal to zero. the critical numbers i got were 0 and e^1/2 however the question says I'm wrong
This might apply:

4. ## Re: Finding critical numbers

sorry thats not correct it's x^-2 * lnx

5. ## Re: Finding critical numbers

What is the domain of that function?

7. ## Re: Finding critical numbers

To find critical points, you find the derivative. Then you set the derivative equal to zero. You then solve for x. Those are then candidates for local maxima or minima.