I was working a fairly simple problem, and then I hit a snag. I know the answer already, and I know that I could find it by plugging it into a graphing calculator, or by simply guessing, but I was hoping that there was some sort of way to solve it with pure mathematics.

cos(x)-xsin(x)=0

That ends up turning into x=cos(x)/sin(x) or x=cot(x).

Is there some way to solve for x, in this situation? Some special rule, or formula, or something? Like I said, I know that graphing it will give you a solution, and random number plugging will solve it as well, but I am hoping a different way. Thanks!