I am to determine the inflection point and intervals where the graph is concave up and concave down, and I have gotten a wrong answer somehow. I'm guessing it's probably when I solved for y'', it was a very long derivative to simplify:

when

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- Nov 6th 2009, 08:59 PMxxlvhConcavity of a function
I am to determine the inflection point and intervals where the graph is concave up and concave down, and I have gotten a wrong answer somehow. I'm guessing it's probably when I solved for y'', it was a very long derivative to simplify:

when - Nov 6th 2009, 09:11 PMVonNemo19
- Nov 6th 2009, 09:16 PMDebsta
...which is equivalent to what xxlvh has above. This gives solution to y'=0 as x=e^2.

In von Nemo19's from it is much easier to find second deriv. - Nov 8th 2009, 09:44 PMxxlvh
I was able to find the inflection point but still having some difficulties with the concavity.

The simplified second derivative is

Here's the inequalities I determined:

For it to be concave up,

and

or and

When I solved these I had

For it to be concave down,

and

or and

And the solution for this one didn't work out at all.

(Headbang)