Find the local maximum and minimum values and saddle point(s) ofthe function. If you have three-dimensional graphing software,graph the function with a domain and viewpoint that reveal all theimportant aspects of the function. (Enter your answers as acomma-separated list. If an answer does not exist, enter DNE.) f(x,y) = 3x^3 ? 9x + 9xy^2
| local maximum value(s) | Â Â Â Â | | Â Â |
| local minimum value(s) | Â Â Â Â | | Â Â |
| saddle point(s) | Â Â Â Â | (x, y, f) = | Â Â |
