could somebody please check my answer if it is correct. the question is: Find the value of f'(-2) if f(x)=(x^2+2) sin(4-3x)

Question

anonymous · Answer

f'(x)= -3(x^2+2) cos(4-3x) + 2xsin(4-3x)

anonymous · Answer

f'(-2) = -18.42

anonymous · Answer

Are you working in degrees or radians?
I can check for you

anonymous · Answer

product rule

anonymous · Answer

Yes, that is correct

anonymous · Answer

i guess they have the answer wrong in the textbook. they had 17.279 as the answer

anonymous · Answer

I would assume so [never trust textbook answers!]


I got the same as you, using product and chain rule!
Maybe if someone else works it out they could confirm this @jim_thompson5910  ?

anonymous · Answer

THX SARAH :)

anonymous · Answer

Anytime :)

jim_thompson5910 · Answer

the book looks like it's working in radians because I'm getting 17.2793719669337 in radian mode and -18.4211322648874 in degree mode

anonymous · Answer

Ah yes; easy mistake to make!
As I said above always make sure you check which form it wants the answer in
[if not stated I would suggest giving it in both - but clarifying which is which obviously]

Thanks jim!

jim_thompson5910 · Answer

sure thing

anonymous · Answer

Thanks guys. i really appreciate it

bradely · Answer

step by step answers posted here http://www.mathskey.com/question2answer/4162/could-somebody-please-check-my-answer-if-it-is-correct ask your calculus homework questions at http://www.mathskey.com/question2answer/ … and get free math help. all the best