Question

what is integration of one upon x

Answer 1

The integration of 1/x is Log(x)

Answer 2

In differential ​calculus we learned that the derivative of ln(x) is 1/x. Integration goes the other way: the integral (or antiderivative) of 1/x should be a function whose derivative is 1/x. As we just saw, this is ln(x). However, if x is negative then ln(x) is undefined!