Calcuculus problem

so, what do I have wrong here:

if x•dx=1/2•x^2... isn't d=1/2?

Is d a variable in calculus? I thought it was part of the notation.

ah, didn't think of that, just thought it was a second variable in the equation

dx denotes the integral.

All I wanted to know was how to prove |x dx =(x^2)/2

I know that you can't just times and divide by dx (now).

It was a stupid question that I probably failed, but I'm still curious as to how anyone can prove it. ermm

This page has a trivial proof using the fundamental theorem, and a sum-based one.

http://math2.org/math/integrals/more/x%5En.htm