I've encountered problem:
and best I came up with is: t = 3 + ih
-ih = -t + 3
ih = t - 3
2 + 4(t-3)
4t - 10
f'(3) = 4???
I suppose, this shouldn't be solved that way, so my question is: how can this type of problem be solved?
I searched for the problem to see if it has any context that would explain the idea of a real-valued function (for real inputs?) that can also have complex inputs and outputs; the problem is found here, which appears to be rather specialized (though I couldn't find the explanation I hoped to find):
A comprehensive introduction to optimization with a focus on practical algorithms for the design of engineering systems.This book offers a comprehensive introduction to optimization with a focus on practical algorithms. The book approaches optimization from an engineering perspective, where the...
My best guess is that you are expected to use the limit definition of the derivative, and hope it will be meaningful.