find critical values for the function sqrt x^2+x-20

Answer 1

Take the second derivative,set to zero, solve for x, then f(x)

Answer 2

I don't know how to do that with the sqrt

Answer 3

sqrt means something to the 1/2 power.

sqrt k= k^(1/2)

derviative of sqrt k= 1/2 * k^-1/2

Answer 4

oh I remember that part but do you do the d/dx of the inside too?