Restricting the domain of a 3D graph

[Ed Elliott]

Is there any way to restrict the function domain on a 3D graph?  The With operator (|) and piecewise work fine with 2D graphs, but not 3D graphs.  I’m fairly new at the CX CAS so perhaps there’s something I’m missing.  But the With operator works fine for 3D graphs on the TI89, so my present thinking is that either there is a bug or it is intentionally unsupported on the Nspire.

 

Specifically, I’m trying to graph (x*y)/(x+y)|x>0 and y>0.  This produces a Syntax Error as does piecewise.  But this same syntax works fine on the TI89.

[Sean Bird]

Good question and request. Piecewise in 3D sounds like a great idea. 

You may not be able to limit the domain with the such that like you could with the 89, but the TI-Nspire sure does graph a lot faster and with a better resolution. It is now actually practical to do 3D.

You could limit the range to view only the region of interest.

When 3.2 comes out with parametric you will be able to control the plot parameters and range separately. 

 

On Wed, Mar 14, 2012 at 9:17 PM, Ed Elliott <eelli...@gmail.com> wrote:

Is there any way to restrict the function domain on a 3D graph?  The With operator (|) and piecewise work fine with 2D graphs, but not 3D graphs.  I’m fairly new at the CX CAS so perhaps there’s something I’m missing.  But the With operator works fine for 3D graphs on the TI89, so my present thinking is that either there is a bug or it is intentionally unsupported on the Nspire.

 

Specifically, I’m trying to graph (x*y)/(x+y)|x>0 and y>0.  This produces a Syntax Error as does piecewise.  But this same syntax works fine on the TI89.

-- 

[Jim Fullerenex]

The möbius strip in OS 3.2 looks awesome!

I hope I can do the beta-testing ;)

Thx for sharing!

Best,

Jim

On 2012-3-15, at 9:52, Sean Bird <covena...@gmail.com> wrote:

Good question and request. Piecewise in 3D sounds like a great idea. 

You may not be able to limit the domain with the such that like you could with the 89, but the TI-Nspire sure does graph a lot faster and with a better resolution. It is now actually practical to do 3D.

You could limit the range to view only the region of interest.

<image.png>

<image.png>

When 3.2 comes out with parametric you will be able to control the plot parameters and range separately. 

 

On Wed, Mar 14, 2012 at 9:17 PM, Ed Elliott <eelli...@gmail.com> wrote:

Is there any way to restrict the function domain on a 3D graph?  The With operator (|) and piecewise work fine with 2D graphs, but not 3D graphs.  I’m fairly new at the CX CAS so perhaps there’s something I’m missing.  But the With operator works fine for 3D graphs on the TI89, so my present thinking is that either there is a bug or it is intentionally unsupported on the Nspire.

 

Specifically, I’m trying to graph (x*y)/(x+y)|x>0 and y>0.  This produces a Syntax Error as does piecewise.  But this same syntax works fine on the TI89.

-- 

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[Ed Elliott]

Sean, thanks!

 

The 3.2 3D Plot Parameters would have given me what I was looking for in the (x*y)/(x+y) case.  But I think that the development team should add the more generic Piecewise-in-3D to the wish list.  Should I submit an enhancement request or do you have an inside track?   I am not TI’s target market so such a request might carry more weight coming from someone who can argue for its use in education.

 

Thanks again,

Ed

--

[Jim Fullerenex]

But the majority of high school students don't need 3D plotting at all (unless they are learning multivariable calculus: highly unlike). 

So this function itself isn't meant for the "target group". Always feel free to give your suggestions! (and welcome to do so!)

Best,

Jim

On 2012-3-15, at 20:55, "Ed Elliott" <eelli...@gmail.com> wrote:

Sean, thanks!

 

The 3.2 3D Plot Parameters would have given me what I was looking for in the (x*y)/(x+y) case.  But I think that the development team should add the more generic Piecewise-in-3D to the wish list.  Should I submit an enhancement request or do you have an inside track?   I am not TI’s target market so such a request might carry more weight coming from someone who can argue for its use in education.

 

Thanks again,

Ed

From: tins...@googlegroups.com [mailto:tins...@googlegroups.com] On Behalf Of Sean Bird
Sent: Wednesday, March 14, 2012 7:52 PM
To: tins...@googlegroups.com
Subject: Re: [tinspire] Restricting the domain of a 3D graph

 

Good question and request. Piecewise in 3D sounds like a great idea. 

You may not be able to limit the domain with the such that like you could with the 89, but the TI-Nspire sure does graph a lot faster and with a better resolution. It is now actually practical to do 3D.

 

You could limit the range to view only the region of interest.

<image001.png>

<image002.png>

 

When 3.2 comes out with parametric you will be able to control the plot parameters and range separately. 

 

 

 

On Wed, Mar 14, 2012 at 9:17 PM, Ed Elliott <eelli...@gmail.com> wrote:

Is there any way to restrict the function domain on a 3D graph?  The With operator (|) and piecewise work fine with 2D graphs, but not 3D graphs.  I’m fairly new at the CX CAS so perhaps there’s something I’m missing.  But the With operator works fine for 3D graphs on the TI89, so my present thinking is that either there is a bug or it is intentionally unsupported on the Nspire.

 

Specifically, I’m trying to graph (x*y)/(x+y)|x>0 and y>0.  This produces a Syntax Error as does piecewise.  But this same syntax works fine on the TI89.

-- 

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[Lana Golembeski]

We have multivariable calc at our school

Sent from my iPhone

Lana

[Jim Fullerenex]

I've said highly unlikely for the *majority*, not those advanced classes which might not even exist in other schools.

Functions like *financial calculator* and eigVc() are also not intended for the "target group". 

My point is to encourage Ed (who seems overcautious) to send an OS update request to TI-Cares. More new features clearly benefit everyone and do no harm.

Jim

[Lana Golembeski]

Absolutely! More and more high schools are adding more upper level courses. Education is rapidly changing!!

Sent from my iPhone

Lana

[Jim Fullerenex]

That's a good thing! I hope they will also add differential equation. ;)
Then the boundary of target group will get blurred :)

Best,

Jim

[Lana Golembeski]

Yes I believe that is coming! I love diff eq!! It really is a fascinating application in mathematics wish I could get my students to appreciate it like i do. They start to put together the concepts in BC calculus.

Sent from my iPad

Lana Golembeski 

[Jim Fullerenex]

Then you might also be an advocate for Laplace(), etc! ;)

Jim

[Lana Golembeski]

Of course! But it has been many years since I used those- back in the 70's! I have forgotten so much but I remember I was vet good at using them!

Sent from my iPad

Lana Golembeski 

[Jim Fullerenex]

Glad to hear that! Hope you can send to TI a request also ;) More votes more possibility to have a new update!

Jim