I have found the second derivative of a function, but am unable to identify the correct command in maple that will allow me to solve for my variable when the derivative is equal to zero. I am attempting to identify the points of inflection. I thought that the command would be similar to the one I used for the first derivative, but it is not working. This is what I tried. (D(D(f)(x)),=0.0,x); I used D(D(f)(x)); to find my second derivative. I used D(f)(x); to find my first derivative and (D(f)(x)),=0.0,x) to find all points where x was equal to zero for my first derivative. I have also tried (D@@2)(f); with no success.