Expressions/equation curves

I am trying to create a curve from an equation- seen and tried to adapt from other threads, but my experession error is -

  1. Expression generated an error for (x, r, b): Right hand value of operator ( is Null

Seems this is a silly error on my part, and hints appreciated.

Cheers (18.6 KB)


A multiplication was missing and I replaced unsupported brackets for parenthesis. (7.7 KB)