How do I find f^-1 (2), x for f^-1 (x) = 0

I have a graph with a function f on it,

f(x) = [ 2x^3 + 1/2 x + 5 ]/2

http://i36.tinypic.com/2ppk190.jpg

And also, it would be great if someone could find the equation for the inverse of f(x)

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- Oct 13th 2008, 07:54 PMrealintegerzInverse functions
How do I find f^-1 (2), x for f^-1 (x) = 0

I have a graph with a function f on it,

f(x) = [ 2x^3 + 1/2 x + 5 ]/2

http://i36.tinypic.com/2ppk190.jpg

And also, it would be great if someone could find the equation for the inverse of f(x) - Oct 13th 2008, 09:29 PM11rdc11
Remember that for inverses the domain and range switch. For example

$\displaystyle f(x)$ has domain A and range B than $\displaystyle f^{-1}(x)$ has domain B and range A

Ok so using this info we can solve what $\displaystyle f^{-1}(x) = 0$ and $\displaystyle f^{-1}(2)$ is since we know the function is

$\displaystyle f(x) = \frac{2x^3 +\frac{x}{2} +5}{2}$

1) $\displaystyle f^{-1}(x) = 0$ is $\displaystyle f(0)=?$

so

$\displaystyle x = \frac{5}{2}$

2)To solve the other problem set

$\displaystyle 2 = \frac{2x^3 +\frac{x}{2} +5}{2}$

and solve for x - Oct 14th 2008, 06:11 PMrealintegerz
hmmm..

im stuck on that f^-1 (2)...

So far i simplified it to...

-2 = 4x^3 + x - Oct 14th 2008, 07:52 PM11rdc11
- Oct 14th 2008, 08:18 PMrealintegerz