In Grapher, can functions be used to define parametric curves? I'm drawing a curve using matrices in Grapher, for instance:



However, any time I try to use a function (i.e. a(x)) as a matrix element:



I get errors:



I've looked through the unofficial manual, but it doesn't specifically say. If I'm not able to use a function as an element, I'd have to re-type the expression in multiple locations whenever I want to change it :(
Just define function a in terms of t rather than in terms of x. For example, the following



produces 3 turns of a helix