# Ahhh guys, is d/dxf(x)=f'(x)?

1. Nov 19, 2012

### Jarfi

ahhh guys, is d/dxf(x)=f'(x)??????

I just don't get it, my classmates are finding the deravative of f(x), i'd think that d/dx(f(x))=f'(f(x))=some annoying long equations...

but they get d/dx(f(x))=f'(x)??? am I doing a silly mistake here?

2. Nov 19, 2012

### Staff: Mentor

Re: ahhh guys, is d/dxf(x)=f'(x)??????

Your classmates are right. Your mistake seems to be in thinking that d/dx is the same as f'. It's not. d/dx is an operator that works on a function; f' already is a function.

$\frac{df(x)}{dx}$ and f'(x) are essentially two different notations for the same thing.

3. Nov 19, 2012

### Jarfi

Re: ahhh guys, is d/dxf(x)=f'(x)??????

damn I'm stupid... well thanks a LOT. It's 1 am but who needs sleep!!!! go homework&euroshopper energy drink