Equation for Tangent Line to Inverse Function at (3,1) of f(x)=x^3+2x^2-x+1

[kathrynag]

Homework Statement

Find an equation for the line tangent to to the graph of f^-1 at the pt (3,1) if f(x)=x^3+2x^2-x+1

Homework Equations

The Attempt at a Solution

I used the Inverse Function Thm
1/(3x^2+4x)
Now do I plug in 3 to this to find slope?
1/21
y-1=1/21(x-3)
y-1=1/21x-1/7
y=1/21x+6/7

 

[blerg]

state the inverse function thm.
what is (3,1) a point of?

also, i think you are mixing up x's. if you look at f^-1 as a function of x, these x's are really values (or y's) of f(x)

i hope you understand this; I'm afraid I've been a bit convoluted.