find the inverse of the function f(x)=x^2 - 3x

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- Aug 21st 2006, 05:04 PMnmathshelp me to find the inverse function
find the inverse of the function f(x)=x^2 - 3x

- Aug 21st 2006, 06:31 PMThePerfectHackerQuote:

Originally Posted by**nmaths**

Because it is not*one-to-one*. For example, $\displaystyle f(3)=f(0)$ and $\displaystyle 3\not = 0$.

Perhaps you mean on a restricted domain? - Aug 25th 2006, 11:38 AMRebesques
Well, you can find an inverse for (say) x>0. The way to find inverses is rather limited: equate y=f(x) and solve for x. That is the inverse function x=g(y).

Here, we have y=f(x)=x^2-3x or x^2-3x-y=0. Solve this (quadratic for x), and you have obtained the inverse function.