Find the derivative with respect to x and the x-coordinate of the stationary point of: y=(4x^2+1)^5

y=(4x^2+1)^5                        y=u^5          u=4x^2+1

                                             y’=5u^4   (wrt u)  u’=8x

y’=40x(4x^2+1)^4

y’=40x(4x^2+1)^4=0             x=0  (x^2+1>0)