math question

03052016, 03:52 PM
Post: #1




math question
or maths, if you are not in the US
I am trying to graph circles on my TI84 plus graphing calculator. I know that the formula for a circle is (xh)^2 + (yk)^2 = r^2 where the center of the circle is (h,k) and the radius is r, but to actually graph the circle I need two formulas (one for the upper part, one for the lower) in the form y1= and y2=, using variables x, h, k, and r. I have found several formulas on the Internet, but none give me the results that I would expect. 

03052016, 04:11 PM
Post: #2




RE: math question
How do I graph a circle on a TI graphing calculator?
Functions can be graphed on TI graphing calculators in the form Y in terms of X. In order to graph a circle, the function for a circle would need to be solved for Y, ie to graph the unit circle (x2+y2=1), first, solve for y, and then input the results into the Y= Editor source: "Graphing a Circle on a TI Graphing Calculator.  Knowledge Base by Texas Instruments  US and Canada" BEST! SlideRule 

03052016, 04:57 PM
Post: #3




RE: math question
Why don't you try a parametric plot?
Mode>Par
\begin{equation} X_{1T} = h + r*cos(T) \end{equation} \begin{equation} Y_{1T} = k + r*sin(T) \end{equation} Zoom>ZSquare or ZDecimal or ZInteger If you insist on using Cartesian coordinates, then Mode>Func
\begin{equation} Y_{1} = k +\sqrt{r^2(xh)^2} \end{equation} \begin{equation} Y_{2} = k \sqrt{r^2(xh)^2} \end{equation} Zoom>ZSquare or ZDecimal or ZInteger 

03052016, 05:46 PM
Post: #4




RE: math question
Thanks SlideRule and Manolo, that's exactly what I was looking for.


03072016, 08:38 AM
Post: #5




RE: math question
You can use following application for this task
https://education.ti.com/en/us/software/...icgraphing There are 4 shapes  circle, ellipse, hyperbola and parabola 

03072016, 09:08 PM
Post: #6




RE: math question
Thanks Klesl, that is a good reference.


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