Calculus Query

[Manoel]

Originally Posted by EricH

C'mon, guys, I haven't had calculus yet and I can tell you that there is a function like this.

Well, you didn't read the question with enough attention. Phrontist wants a function such that its derivative is equal to its inverse, not the function itself.

Originally Posted by EricH

A function is any line or relation where any input has one and only one output, right?

No, not at all. My previous example of y = x^2 would not be a function if you were correct. You described a bijective function, but there are also injective and, the ones that disproves you, surjective functions.

Originally Posted by EricH

So a straight diagonal line is a function, correct? Now, the only function that will equal its own inverse has to have a slope of -1. So, any function whose equation reads something like f(x)=-x+b with any value for b will be its own inverse. Was that so hard?

Yeah, that is correct if you disregard the derivative part of the problem.