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# Inverse Function on HP Prime question

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HP PRIME

Hello  ,

I was wondering if anybody new how to find the inverse of a function algebriac expresion on the HP Prime.

This can be done on the Casio Class Pad using the invert function. Look at video link below .

So my question can a similar thing be done on the HP PRIME.

Regards

Arthur Rappos

ClassPad Help 172 - Inverse Of A Function
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Yes, it's done on the HP Prime almost the same way as on the ClassPad.  Just be sure to be in CAS, not Home.  Here's a screen shot (I hope the forum displays it ok):

Hope that helps!  Disclaimer: I don't work for HP. I'm just another HP calculator enthusiast.

-Joe-
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Hello Joe,

I cant see the image you have posted.

Regards

Athanasios

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The forum says that my image upload is "Awaiting Approval".  I hope it appears soon.  If not, here's a link to it on my web server: http://holyjoe.net/images/isolate.png

Meanwhile, you can find the inverse function of almost any y=f(x) by simply solving that equation for x using the solve command in CAS.  This is sometimes referred to as "isolating x".  For example, if y=1+2/x, you can find the inverse function in Prime's CAS by typing this:

solve(y=1+2/x,x)

This isolates the x to the other side of the equation, giving us x=2/(y-1), which shows us the inverse function we were looking for.

The solve command can isolate almost any variable from almost any equation.  It's very powerful.

-Joe-
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Hello Joe,

Thankyou very much for that, it worked as you said.  Can I ask you where do you get a  good reference  book for using this calculator.  How did  you find out about the deeper use of solve().

Regards

Athanasios

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Hi!, @Athanasios:

See, the images, for solve, the example in the video, in Wolfram Alpha ...

The inverse ...

Kind Regards !.
Have a nice day !.
Provost in HP Spanish Public Forum ... https://h30467.www3.hp.com/
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> Can I ask you where do you get a  good reference  book for using this calculator.

The best place to start is the HP Prime User Guide.  It's almost 700 pages of important information.  Just run the emulator (which comes with the calculator) and click on its Help menu to get to the User Guide in PDF format.  The benefit of getting it that way is that the emulator automatically updates itself with the latest version, including the latest available User Guide.

> How did  you find out about the deeper use of solve().

Finding inverse functions by solving for (isolating) the independent variable is something I learned in Algebra class in 8th grade many, many, many years ago. 🙂

-Joe-
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Hi!, Joe_Horn:

Kind Regards !.
Have a nice day !.
Provost in HP Spanish Public Forum ... https://h30467.www3.hp.com/
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Were you able to graph the inverse on the HP Prime?

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@Calc67 wrote:

Were you able to graph the inverse on the HP Prime?

If by "you" you mean me, and if by "the inverse" you mean 2/(X-1), then yes:

Sometimes images don't appear on this forum correctly; if the above isn't displaying correctly, here's a direct link to it:

http://holyjoe.net/Prime/inverse.png

The inverse function is graphed exactly the same way as the original function; just type it into the Function app and hit Plot.

If by "you" and/or "the inverse" you meant something else, please clarify your question.

-Joe-
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