also, if he means the inverse of the log to be 1/log(x), that's not so simple, and none of you have even mentioned the correct answer to that derivative. He didn't say natural log, so it's not necessarily ln(x). The real answer is actually f'(x)=-1/((ln(x)^2)*x) for f(x)=1/log(x), and I had to pull maple out to do that because I'm lazy and didn't feel like actually doing the nasty little limit involved in doing that. Actually, now that I look over most of the replies on here, it's pretty clear that most of you don't know anything about math. And most people who are proficient in math (i.e. professors and math majors) will often commonly use 1/f(x) to be the inverse of f(x). Same with physics professors, engineering professors, in fact I've heard it from yale grads, harvard grads, etc...

Really? Just because he works at McDonald's he's supposed to be stupid? Him working there is probably why he caught your mistake in the first place.

the only thing remotely interesting is all the idiots cyber-wanking over their superiority in math over the OP; just like you don't care about him being AP calc, similarly nobody gives a hoot over you being the master of the math-universe (or so you think).

Don't sweat it, no real mathematician can do sums in their head. What do you think a calculator is for? (Now, if you were a physicist, you'd be in trouble.)

you made a mistake, go cry me a river fucktard.

dude you fail... I'm in pre calculus in highschool.., we learned that shit last year -.-

Just because you're a calculus student doesn't mean that you are immune to simple math mistakes. After all, the stuff you're learning is all based on simple math, anyway. Not an FML, especially since McDonald's employees are generally assisted by the cash registers.

You're an idiot trying to sound smart. The inverse of a logarithm is simply an exponential function. The derivative is easy to find once you have a simple polynomial. Did it ever cross your mind that the McDonald's worker is also an AP student, working to have a little extra money to pay for college?

wtf, just because he works at mcdonalds, doesnt mean he can't count mister math genius.

Did lol. We learned that in maths when I was about 16.