How would you find the local maxima and minima for y= xe^-x

Im not sure how to do it and would appreciate very much if someone could help me.

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- Oct 16th 2009, 08:17 PMfvaras89local maxima and minima
How would you find the local maxima and minima for y= xe^-x

Im not sure how to do it and would appreciate very much if someone could help me. - Oct 16th 2009, 08:21 PMTKHunny
Generally, you would examine it for continuity, then find the first derivative. Where the first derivative exists and is zero, this is likely to be a local max or min. That's only part of the story, of course. You tell me the rest.

Can you find dy/dx? It will take the Product Rule. - Oct 16th 2009, 08:24 PMfvaras89
so y'= (e^-x)(-x e^-x)

= e^-x(1-x)

so do u let y'= 0?

if so, i put e^-x(1-x)=0 and thats when i got stuck

so what do i do next? - Oct 16th 2009, 10:17 PMmr fantastic
- Oct 17th 2009, 08:19 AMTKHunny
- Oct 17th 2009, 09:15 PMfvaras89
I just thought u could take out the common factor like i did before or would there be another way to present it?

- Oct 18th 2009, 06:50 PMTKHunny
I think it would help if the addition actually appeared in the first equation. Thus my encouragement to be more careful. I have little doubt that you had the correct thing in your mind, you just didn't write it.