Our school teachers have nothing to do anymore. Google checks spelling, Google replaces books and encyclopedias, Google solves math problems… It couldn't do the only thing: create 3D graphs for complex equations. But those times are far away as well.
So these graphs are fully interactive, dynamic and can be easily changed and explored.
You can test the function yourself by searching, say, sqrt(x*x+y*y)+3*cos(sqrt(x*x+y*y))+5. After Google shows the image, you can zoom it in or out by pressing '+' or '-' buttons accordingly, rotate it with your mouse or by pressing the 'Play' button on the screen. Enjoy :)
Oh, I've forgotten. The function is only available to you if your web browser supports WebGL (meaning, Chrome of Firefox). Now, enjoy :)