Hi.

I'm having problems understanding $\displaystyle \frac{dy}{dx}\(\frac{1}{x})$

I always get 0 when I try to solve it with conventional algebra but the answer is $\displaystyle \frac{-1}{x^2}$

Bonus question: How do I get the enclosing brackets in my tex code to cover $\displaystyle \frac{1}{x}$ completely, instead of being small? Also, how do I do a space between $\displaystyle \frac{dy}{dx}$ and $\displaystyle \frac{1}{x}$ ?

Thanks!