posted by Andrea .
At what interval is e^(-5x^2) concave up?
I know the second derivative is
but I just can not figure this one out.
Thank you for your help!
Then this for second derivative and graph
Note that you did the second derivative correctly. It is easier to write it their way y" = 10e^(-5x^2)(10x^2-1)
It is zero at x = +/- .316
so it is positive for x>.316
and for x <.316