Can Grapher evaluate a function? I just noticed that Grapher fails to evaluate a function at a constant.  In the image, the graph of y = c should of course be a horizontal line.  Is there a way to fix or work around it?  This seems like such a fundamental bug that I can't understand why I haven't run into it before.
Well, the problem is that Grapher assuming that the x in f(x)=x^2 means the x coordinate.

To fix this problem, you should change the x to some other variable (say z).

I know, Grapher is weird sometimes.