I'm French, so i have the circumflex on my keyboard
I didn't differentiate. I know a derivative of sin(x). This is the basic definition of a derivate number...Unless I looked at it wrong (which you know I do all the time ) you just differntiated and go the same result...
If i get an indeterminated form with it, i guess i would have one with l'H˘pital's rule too...but what if you were unsure if applying that method didnt yield another indeterminate form?
Don't you think that the definition of the derivate number came BEFORE l'H˘pital's rule ?because you applied l'hopitals rule except instead of doing f'(x) then evaluating at 0 you jsut went straight