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 Inverse of a Function
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whoareyou




PostPosted: Wed Sep 12, 2012 9:43 pm   Post subject: Inverse of a Function

Could someone please explain guide me in the right direction as to how to find the inverse of this function?
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Aange10




PostPosted: Thu Sep 13, 2012 8:09 am   Post subject: RE:Inverse of a Function

if y = 1/2 (e^x - e^-x) then the inverse is switching the x and y.

x = 1/2 (e^y - e^-y).
whoareyou




PostPosted: Thu Sep 13, 2012 8:10 am   Post subject: RE:Inverse of a Function

Yeah I got that much, but how would you then isolate for y?
Zren




PostPosted: Thu Sep 13, 2012 1:33 pm   Post subject: RE:Inverse of a Function

Found this. No idea how they got from a -> b though.

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Edit: Ah. Totally forgot about what negative exponents actually represent.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

So essentially they write it as:

(1/2)(e^x - (1/e^x))

Which they factor out:

(1/2)(1/e^x)((e^x/(1/e^x)) - 1)
(1/2)(1/e^x)((e^x * e^x) - 1)
(1/2)(1/e^x)(e^2x - 1)
bl0ckeduser




PostPosted: Fri Sep 14, 2012 8:37 am   Post subject: Re: Inverse of a Function

I have no idea how to help you with this problem, but in light of Zren's saying the function is the same as sinh, maybe this page, which deals with the inverse of sinh, will help.

http://en.wikipedia.org/wiki/Inverse_hyperbolic_function
Zren




PostPosted: Fri Sep 14, 2012 11:45 am   Post subject: RE:Inverse of a Function

Ah. Looks like the hotlinked image is down.
http://www.purplemath.com/modules/simpexpo2.htm

Basically it stated that:

x^-y = 1/x^y
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