http://www.wolframalpha.com/input/?i=2*%28%2813-x%5E2%29%2F12%29%5E2-1%3D%2840-y%5E2%29%2F24%2C+4*%28%2813-x%5E2%29%2F12%29%5E3-3*%2813-x%5E2%29%2F12%3D%2845-%28x%2By%29%5E2%29%2F36