Graph a Circle on the TI 84 Plus CE Calculator

Graph a Circle on the TI 84 Plus CE Calculator


Hi this is Rob. I am going to show you how to graph a circle
on the TI 84 Plus CE Graphing Calculator. To graph a circle on the TI 84 Plus CE we
are going to use the Conics App that is built into the calculator. To open the Conics App, press the apps button
here. The Applications list opens up. Go down to number 4, Conics and press enter. The types of conics that you can graph with
the Conics App are circles, ellipses, hyperbolas and parabolas. Go down to number 1, Circle and press the
enter key. Now we see two standard equations for a circle. The first equation is referred to as the standard
form and is also referred to as the center-radius form. The second equation is known as the General
Form equation for a circle. The general form is basicly the first equation
multiplied out. In this video we will use the first equation
and we will graph the following circle: x minus 3 squared plus y plus 4 squared equals
25. On the calculator choose one and press enter. This screen appears. To graph the circle we will need to know H,
K, and R. The numbers below are from a previous circle equation that I was graphing. Using our equation, H equals 3, K equals a
negative 4 and R squared equals 25. Now let’s plug in these numbers into the
calculator. H equals 3. I already have a 3 there. Now use the down arrow key and go to K. And
enter a negative 4 for K. Remember to use this negative sign here and not the minus
sign. But Rob, why use a negative four, it looks
like a positive 4. Well, the equations is y minus a negative
4. And a negative times a negative is a positive. That is why in the equation it is y plus 4. Go down to R. Now R squared equals 25. Thus take the square root of both sides and
R equals a plus or minus 5. Enter a positive 5 for R. Now press this graph
button here to graph the circle. Unfortunately the numbers of the graph are
not labeled. But you can press this trace button here and
then use the right or left arrow buttons to trace around the circle. The calculator will display the coordinates
of the trace on the bottom of the screen. To escape out of the trace, press the clear
button here. Remember, the center of a circle is at H,
K. In this equation, the center of our circle
is at 3, negative 4. To escape out of this graph, press the clear
button here. It will bring you back to this screen and
you can graph your next circle. To escape out of this screen press this y
equals key here. It will bring you back to this screen. Ok that is it. That is how to graph a circle on the TI 84
Plus CE Graphing Calculator. If you like this video, please give it a thumbs
up and please subscribe to this channel.

5 thoughts to “Graph a Circle on the TI 84 Plus CE Calculator”

  1. The conix app is not on either one of my 3 8I-84 Plus CE and silver editions. Where are you getting this from?

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