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shanazky
Apr 19, 2009, 06:37 PM
find the inverse of each function and state whether the inverse is a function

f(x) = x^3 - 4

f(x) = (x-1)^2

Gernald
Apr 19, 2009, 07:46 PM
If I remember right you just make the function negative to find the inverse and then you graph the inverse to see if it passes the vertical line test to see if it's a function or not.

so with the first one I think it would be -X^3+4 and then you'd graph it to see if it's a function or not.

Not positivie though... someone correct me if I'm wrong.

try purplemath.com it can help a lot if your having trouble with this sort of stuff.

Perito
Apr 19, 2009, 08:35 PM
Gernald is not correct, but I don't feel like giving him a "reddie".

Inverse functions:

Inverse function - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Inverse_function)

Finding the Inverse of a Function (http://www.purplemath.com/modules/invrsfcn3.htm)

Basically, you have a functions:

f(x) = x^3 - 4

and f(x) = (x-1)^2

Replace the "f(x)" with "y" the "dependent variable"

y = x^3 - 4

and y = (x-1)^2

Solve for x. Replace x with "f(y)". You now have f(y). You changed the dependent variable (y-axis) to the independent variable (x-axis). Now you have to see whether it is a function. The definition of a function is that for every value on the independent-variable axis, there is one, and only one, value on the dependent-variable axis (for every x, there is one and only one y). See if for every y (plotted on the x-axis), there is one and only one x.

Gernald
Apr 22, 2009, 06:07 PM
Lol... thanks SHE appreciates it.
As soon as you showed how to do it I wanted someone to smack me... what was I thinking!!
:-)