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URGENT question on second derivative :) (1 Viewer)

Dr_Doom

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Hi!!!

When finding the local max, min and inflection points of f(x) = x^2 e^x

When I'm finding f''(x) = 0
I have to use quadratic forumula. But I end up having to square root minus 4. Which you can't do. So does anyoine know a way I can find the inflection points??

Could someone please tell me if I'm doing it right.

f'(x) = 2x e^x + x^2 x e^x
= xe^x (2+x)
x = 0 and -2

f(0) = 0
f(-2) = 0.54134

So local max and min are (0,0) and (-2, 0.54)

Then
f''(x) = 2e^x + 2xe^x + 2xe^x + x^2 e^x
= 2e^x + x^2e^x + 4xe^x
e^x (x^2 + 4x + 2)

Quadratic forumula:

-4 +- [sqrt]-4 / 2

= syntax error....

PLEASE HELp :)

Dr_Doom
 

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