View Full Version : Inverse function theorem for 1 variable
gamitor
Sep19-09, 03:51 PM
Dear all,
Does anybody knows any the proof for Inverse Function Theorem for single variable function or link where I can find that proof?
Thank you in advance
Office_Shredder
Sep19-09, 03:59 PM
The statement for a single variable is that if f:R->R is continuously differentiable, and f'(a) is non-zero, f is locally invertible. But if f'(a) is non-zero, it must either be greater than 0 or less than 0. So on some interval around a, f'(a) is always positive or always negative. What can you conclude?
Are you looking for the proof to
http://upload.wikimedia.org/math/f/9/2/f929249264cd047793a334dc442e0006.png
where b = f(a) as shown here?
http://en.wikipedia.org/wiki/Inverse_function_theorem
gamitor
Sep19-09, 04:04 PM
Are you looking for the proof to
http://upload.wikimedia.org/math/f/9/2/f929249264cd047793a334dc442e0006.png
where b = f(a) as shown here?
http://en.wikipedia.org/wiki/Inverse_function_theorem
yes, exactly, but I cannot find anywhere the proof for single variable functions, do you know where it is?
Start with
f(f^{-1}(x)) = x
Differentiate both sides, then solve for f-1'(x)
gamitor
Sep19-09, 04:21 PM
Start with
f(f^{-1}(x)) = x
Differentiate both sides, then solve for f-1'(x)
Thanks a lot!!!
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