what is a inverse

http://www.wolframalpha.com/widgets/view.jsp?id=d08726019e4a2a15cb1d49092e4d0522

http://tube.geogebra.org/m/110153

Thanks for that link, radix.....I had no idea that WolframAlpha had something like that.......

I didn't know GeoGebra did either!

Thanks Radix !