Quote Originally Posted by Mikey_R View Post
Whilst, yes, calculus is more complex than basic maths, we can both also agree that differentiating X^2 is vastly less complex than integrating ln(Sin[x^2]/Tan[Cos{X}]) or what other made up nonsense you can come up with that will be difficult to do. SO, where is the complexity line drawn?
Complexity exists on a scale, a spectrum. There's generally broad agreement on the relative positions of things on this spectrum.

For the purposes of discussion, it's sometimes convenient to take a chunk of that spectrum and label it "simple", another chunk "complex", and so on. How that's done is more likely to vary from person to person.