Is there a way to draw shape/circle with equation in the form of x^2+y^2=4

[phil]

Circle would be one example, such as x^2+y^2=4,
I KNOW circle could be drawn by going to "Shapes"-->"circle"

What I actually want to draw is a heart shape, which has the equation
of:
(x^2+y^2-1)^3-x^2y^3=0

I did a lot of searching to solve this but no luck.
I was able to draw a heart in polar form, but I really just want to
know,
is it possible to draw the shape of equation x^2+y^2=4??

Thanks!!

[Sean Bird]

On our TI-Nspire Google Group Website, there is a file called hearts,

https://sites.google.com/site/tinspiregroup/assignments/hearts.tns?attredirects=0&d=1

if you are using the TI-Nsire CAS, you can do this with the zeros(expression,y) command. 

You can also see this described at  http://bird-godlydominion.blogspot.com/2009/02/graphing-hearts.html 

and there is a pdf of a heart tns file on my Nspire calculus website at http://covenantchristian.org/bird/TTT/NspireCalc/Day15Sec8_9HEARTS.pdf

John Hanna has a file that enables you to do some implicit graphing on a numeric TI-Nspire.

Thanks for asking. Implicit graphing is a often requested.

- Sean Bird

[Eric Findlay]

Wasn't there a post hinting this could be in a near future update?  Or am I just imagining things?

  --Eric

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[phil]

Thanks for the prompt reply Sean!

#1. when I used the zeros() function, I am able to get the heart
shape, however the top half and lower half of the heart has two
different colors.. any reason?

#2,This is so cool, esp that 3d heart shape, can you please post the
equation z(x,y) to plot the 3d heart?

thanks!


On 22 Feb, 14:35, Sean Bird <covenantb...@gmail.com> wrote:
> On our TI-Nspire Google Group Website, there is a file called hearts,https://sites.google.com/site/tinspiregroup/assignments/hearts.tns?at...
> if you are using the TI-Nsire *CAS*, you can do this with the
> zeros(expression,y) command.
> You can also see this described athttp://bird-godlydominion.blogspot.com/2009/02/graphing-hearts.html
> and there is a pdf of a heart tns file on my Nspire calculus website athttp://covenantchristian.org/bird/TTT/NspireCalc/Day15Sec8_9HEARTS.pdf

[John Losse]

Yes, you can do this using the "zeros method".

[Sean Bird]

#1) They are two parts of a function. For example, graph f1(x)={1,-1}x

  It is like the automatic changing colors when you graph f1(x) and then f2(x).

  You, of course, can change the color with a right-click.

#2) See page 1.7 of the heart.tns file

zeros((x^(2)+((9)/(4))*y^(2)+z^(2)-1)^(3)-x^(2)*z^(3)-((9)/(80))*y^(2)*z^(3),z)

- Sean Bird

Covenant Christian High School

Indianapolis, IN

[phil]

Thanks very much Sean, I got it now, I changed both curve's color to
same thing.

I guess I just don't understand why is it two functions instead of
one, we are plotting the solution of some equation equals to zero (by
using the Zeros() method), to me it is one function instead of two.

f(x) = zeros(x^2 + y^2 -4, y)

is essentially plotting the set of solutions of the equation x^2 + y^2
-4 = 0, which is same as plotting all the pairs of values of x&y
satisfying the equation x^2 + y^2 = 4...

[Sean Bird]

If you solve the zeros() command on a calculator application, you see that you get two solutions, essentially the positive and negative portion. 

{piecewise(−√(4-x^(2)),x^(2)≤4),piecewise(√(4-x^(2)),x^(2)≤4)}

[Travis Bower]

Out of curiosity, any way to get the function to appear near the curve [and not just the f1 label]?

With the {-1.1} method.

[Sean Bird]

I used right-click (ctrl menu) to show the 'Label' and then 'Attributes', label style. Shown in the image above are 3 of 5 label style and 5 of 5 in the red. This was for the f1(x)={-1,1}x example

- Sean Bird

T³ - Teachers Teaching with Technology - Instructor

T³’s mission is “to provide quality professional development that enables the mathematics and science educator to be successful in the classroom through the appropriate use of technology."

blog: http://bird-godlydominion.blogspot.com/
Covenant Christian High School 

http://www.youtube.com/user/covenantbird/videos

[Travis Bower]

I will keep fiddling with it.

I can't do it in Scratchpad nor document.

Anyone else try this?

--

[Sean Bird]

According to your image it looks like you are close. Change the attributes of the line. Last choice is label style. I think you want the 3rd or 5th choice.

[Marc Garneau]

Works fine for me using Sean's instructions, in a document or in Scratchpad.

On 2012-02-23, at 6:55 AM, Travis Bower wrote:

I will keep fiddling with it.

I can't do it in Scratchpad nor document.

Anyone else try this?

On Thu, Feb 23, 2012 at 4:19 AM, Sean Bird <covena...@gmail.com> wrote:

<image.png>

<02-23-2012 Image009.jpg>

[Travis Bower]

I think I am doing what Sean suggests.
Any other ideas?

[Travis Bower]

I have up to date software.  3.1.0.392
Hey TI tech support, could you look into this?

[Sean Bird]

Sorry Travis, you are using the TI-Nspire and not the TI-Nspire CAS.

I really appreciated the original question. It is nice to have the graph labeled with something more meaningful than f1_1. Sorry it won't happen for you, perhaps for a similar reason you couldn't just say f1(x) on a Calculator or Notes page and get what the function is.

- Sean Bird

[phil]

Sean the heart.tns is AWESOME!! esp with the nice details/
instructions.

Took me a while to figure out how to upload the file to my calculator
but it is well worth it.

This thread ends all my questions regarding drawing heart/circle, I
hope other people with same question could find this thread
(I didn't find anything to solve this by googling)

Again big thanks to Sean