Complex plotting question

[John Keith]

When plotting the real and imaginary parts of a complex-valued function, the Prime draws one plot first, then the other. For example, in the Function app:

Code:


F1(X)=RE(Zeta(0.5+X*i))
F2(X)=IM(Zeta(0.5+X*i))

This results in the function being evaluated twice for the same input values. Is there a way to plot both parts with one function or otherwise avoid the repetitive calculation?

Thanks,
John