Inverse of a function

[Pharmacist2be]

Advertisement - Members don't see this ad

How would you solve this one?
If f(x) = x3(cubed)+2x2(squared) and g is the inverse of f, then g prime(derivative) (3) is?
a)1/12 b)1/8 c) 1/5 d)1/2

it's on collins notes..

 

[pharmschooler]

I know you're going to get the standard "SDN is not for homework help" shutdown soon, but I'd really advise you to check out Khan Academy. Lots of videos for help with math. All free! Google it.

 

[Jabberwocky12]

since you have the y value (f(x)) the inverse is where you substitute the X and Y. So now you would have for the inverse X= y^3 + 2y^2. Solve for y again and that is the inverse.

Once you solve for the new y of the inverse, take the derivative of it. Once you do that, substitute X for 3.

Too lazy to work it out myself but it looks right. Someone want to correct it for me if I'm wrong? It's been ages since I took calc. As a general rule, multiplying the slop of the original and inverse equation together gives you -1.

I don't think the homework help issue falls here since it is for study guides and MCAT has a similar section. However, PCAT gets calculus while MCAT gets physics so this seems like the best place to go.