1. ## Integral of 1/x^2

Hi there, I am here for some major help in the Advanced Aplied maths forum and thought this small question is better asked here.

I have as part of a larger integral $1/x^2$, the answer to which i believe to be $-1/x$. Could someone please explain to me how this is obtained?

The entire integral if it is helpful is:

$\int^{2}_{1}(1/x^2 + cos x) dx$

2. Polynomial or Exponent Rule?

$\frac{d}{dx}(-\frac{1}{x}) = \frac{d}{dx}(-x^{-1}) = -(-1)x^{-2} = \frac{1}{x^{2}}$

3. ## Thanks

Thanks, that makes sense now, because there is so much math i don't know, i forget the simple things expecting it to be something more difficult, of course i was forgetting that

$\frac{1}{x^2}$ is the same as $x^{-2}$

EDIT: What is the diff between the Plynomial and Exponent rules? I am unfamiliar with different rules for integrating things.