find the inverse function if f(x)=x^2 - 3x
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find the inverse function if f(x)=x^2 - 3x
f(x)^-1
i.e 1/(x^2-3x)
Welcome to the Forums :wave:
No no no. That is not the inverse of a function. That is 1/f.
Look up "completing the square" on Google.
f(x)= x2 - 3x
To find inverse first complete the square to get it in form
f(x) = (x - a)2 + b for some constants a and b
Then to find inverse write
y = (x - a)2 + b
Swap the x's and y's
x = (y - a)2 + b
Then rearrange to make y the subject
Then replace y with f-1
Oh and to have an inverse you will need to restrict the domain as the function does not have an inverse if you take the domain to be the set of all real numbers. Perhaps you left out the domain in the question. The actual domain will affect the final answer.
Zaza, you're totally right. My bad. Man, school can't come sonner can it. :sick:
Exactly...Quote:
Originally Posted by Glaysher
This is the way to find the inverse of a function.
If we get f(x)^-1, it gives that 1/f(x). It's not the invers of a function.
If you are fine with a cartesian plan, check that 1/f(x) is a inverse of f(x).