Question

Check my answer?

Answer 1

I got -1/5

Answer 2

@Photon336 @agent0smith @mww

Answer 3

these questions are really tricky to nme for some reason

Answer 4

@campbell_st

Answer 5

Just use the formula for the derivative of an inverse function

Answer 6

Got it, thank ya sir

Answer 7

http://tutorial.math.lamar.edu/Classes/CalcI/DiffInvTrigFcns_files/eq0001P.gif

Answer 8

or http://image.tutorvista.com/content/feed/u837/inverse.PNG
\[\Large (f^{-1})'(-4) = \frac{ 1 }{ f' ( f^{-1} (-4)) }\]

Answer 9

Then \[\large f^{-1} (-4) = 2\] (remember it means find x when y=-4)
so \[\large f'(f^{-1} (-4)) = f'(2) = -5\]

Answer 10

So yes -1/5 is right.