The equation is x^2 + y^2 = 9

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- Aug 7th 2011, 08:19 PMbenny92000How do you graph a circle with the TI-83 plus calculator?
The equation is x^2 + y^2 = 9

- Aug 7th 2011, 08:56 PMBacteriusRe: How do you graph a circle with the TI-83 plus calculator?
There are different ways to do it.

**Cartesian method (y = f(x))**

You will need two functions because of the limitations of the cartesian coordinate system, obtained by rearranging the circle equation in terms of x:

$\displaystyle y = \sqrt{9 - x^2}$ and $\displaystyle y = - \sqrt{9 - x^2}$

**Polar method**

This one is simple.. $\displaystyle r = 3$, since the radius of a circle is constant.

**Parametric method**

Use the trigonometric functions $\displaystyle X_t = 3 \cos{(t)}$ and $\displaystyle Y_t = 3 \sin{(t)}$.

You can change the type of graphing method in the setup menu of your TI. - Aug 7th 2011, 11:15 PMbenny92000Re: How do you graph a circle with the TI-83 plus calculator?
What is the preferred method?

- Aug 7th 2011, 11:23 PMBacteriusRe: How do you graph a circle with the TI-83 plus calculator?
Umm.. whichever, they all produce the same circle. It's up to personal preference and context.

I would personally recommend the parametric method because it's easy to change the center of the circle if you need to (as well as the radius of course). - Aug 7th 2011, 11:24 PMmr fantasticRe: How do you graph a circle with the TI-83 plus calculator?