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# Finding inverse of a function help? watch

1. say for example
f(x)=(x-1)/(x+1)

so i would do
y=(x-1)/(x+1)
y(x+1)=x-1
yx+y=x-1
y+1=x-yx
y+1=x(1-y)
x=(y+1)/(1-y)

But apparently this isn't the right answer and the teacher always gets something else, can you guys help me out?
2. (Original post by ErniePicks)
say for example
f(x)=(x-1)/(x+1)

so i would do
y=(x-1)/(x+1)
y(x+1)=x-1
yx+y=x-1
y+1=x-yx
y+1=x(1-y)
x=(y+1)/(1-y)

But apparently this isn't the right answer and the teacher always gets something else, can you guys help me out?
That is pretty much the correct answer, though I'm not sure if you need to swap x for f^-1(x) and y for x.
3. That's correct, you just have to swap the x with f^-1(x) and y with x

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Updated: November 5, 2015
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