Re: Where does the sign go?

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

Re: Where does the sign go?

Quote:

Originally Posted by

**szucslaszlo** I am having trouble calculating a very simple derivative, namely the derivative of cos(1/x).

$\displaystyle \frac{d}{{dx}}\left[ {\cos \left( {\frac{1}{x}} \right)} \right] = \frac{1}{{x^2 }}\sin \left( {\frac{1}{x}} \right)$

Re: Where does the sign go?

Quote:

Originally Posted by

**Siron** $\displaystyle \frac{d}{dx}\left(\frac{1}{x}\right)=\frac{-1}{x^2}$

Oh, I am so embarrased. Thank you!

Re: Where does the sign go?