Hi everyone. My friend has showed me how to solve this particular problem (attached picture) and the solution (also attached) is, apparently, pretty simple. Despite that, I don't understand why the indefinite integral of e^{x}is still e^{x}. Aren't you supposed to add 1 to the exponent and then put that same value on the denominator? I don't get why its integral is the same... Please clear my confusion.

Thank you very much for your help!