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Inverse of a Function

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Calculators: Casio fx-9860GII, Casio Classpad fx-CP400

Inverse of a Function

Postby PsySc0rpi0n » Sat Jun 16, 2018 1:58 pm

Hello again.

I know I can plot te inverse of a function. But is it possible to analytically evaluate the expression of the inverse function of a given expression?

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Calculators: Casio fx-9750GII, Casio fx-9750GII (SH4), Casio fx-9860GII, Casio fx-CG50

Re: Inverse of a Function

Postby lephe » Mon Jun 18, 2018 10:29 am

You could just rotate the calculator 90°. Otherwise you're stuck with the serious problem that only few functions are invertible; an analytical inversion process seems out of the question. Even polynomials are mostly not injective, so you're definitely not going to get an expression by calling a built-in calculator functionality.

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Posts: 40
Joined: Tue Dec 17, 2013 12:56 pm
Calculators: Casio fx-9860GII, Casio Classpad fx-CP400

Re: Inverse of a Function

Postby PsySc0rpi0n » Wed Jun 20, 2018 5:45 pm

Well, maybe if I describe the problem, it gets easier to understand.

I'm testing an electronic circuit and I'm registering some values I'm reading with the scope from that circuit. With those values, I plot a curve in a Spreadsheet. Then I ask the Spreadsheet program to give me the Trend Line expression using the Quadratic Law. After that I wanted to obtain the inverse function of the expression SpreadSheet gave me. I'm doing it by hand but if the calculator could give it to me, it was great!

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