Add support for graphing implicit functions

[jrkimber]

When trying to graph the function x^3+y^3=3xy, it says 'not handled'. Could the grapher be improved to handle implicit functions such as these?

Thanks

[crt333]

This would be helpful for teaching AP Calculus BC

[adri1numworks]

This request has already been identified internally. However, it represents an important effort of development while it is not a priority. I leave this request opened and will let you know of any change