if f(x)=1/3x-1 and g(x) = f^-1(x), find g’(x).

Question

bibby · Answer

we literally just did this?

lexi724 · Answer

g o f) (x) = 2 ( 3x^2 - 1) = 6x^2 - 2 

two: 
An = 5 * 2^n 

three 
can't do with text

anonymous · Answer

Thats incorrect darling

bibby · Answer

Don't patronize her

anonymous · Answer

Please reference this question http://openstudy.com/study#/updates/52c33e98e4b0b729fb8c0a95

anonymous · Answer

is it $$f(x)=\frac{1}{3x-1}$$??

bibby · Answer

whoops

anonymous · Answer

@satellite73 yes

anonymous · Answer

one method is to actually find the inverse, and then take the derivative of that

anonymous · Answer

not too hard to find 
$$x=\frac{1}{3y-1}$$
$$3y-1=\frac{1}{x}$$
$$3y=\frac{1}{x}+1$$
$$y=\frac{1}{3x}+\frac{1}{3}$$ or 
$$f^{-1}(x)=\frac{1}{3x}+\frac{1}{3}$$ now the derivative is easy to find

anonymous · Answer

i mean i guess it is easy to find, right?

anonymous · Answer

1/3

anonymous · Answer

oh heck no

anonymous · Answer

grrrr

anonymous · Answer

the derivative of $\frac{1}{x}$ is $-\frac{1}{x^2}$

anonymous · Answer

so the derivative of $\frac{1}{3}$ is $-\frac{1}{3x^2}$

anonymous · Answer

oops typo there, i mean the derivative of 
$$\frac{1}{3x}$$ is 
$$-\frac{1}{3x^2}$$