SOLUTION: Hello there, I have a project due monday about graphing circles using my ti-83. there are four assingment and the 1st of four is to graph a few concetric circles with an origin of

Algebra ->  Graphs -> SOLUTION: Hello there, I have a project due monday about graphing circles using my ti-83. there are four assingment and the 1st of four is to graph a few concetric circles with an origin of      Log On


   

Question 581859: Hello there, I have a project due monday about graphing circles using my ti-83.
there are four assingment and the 1st of four is to graph a few concetric circles with an origin of (0,0).
I must write my equations in (x+h) squared + (y-K) squared = radius squared.
but then I must solve for y
. what i dont understand is how to solve for y
please give me an example on how to do this problem then i can do the rest on my own. Thanks
Answer by KMST(5398) About Me  (Show Source):
You can put this solution on YOUR website!
A circle with radius r, centered at point (h,k) has the equation
%28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2
Your circles, centered at (0,0) will have the equation
x%5E2%2By%5E2=r%5E2
For a radius of 2, since 2%5E2=4, the equation would be
x%5E2%2By%5E2=4
Solving for y, you will get two functions, representing the top half of the circle, and the bottom half of the circle.
x%5E2%2By%5E2=4 --> y%5E2=4-x%5E2
Then for the top half
y=sqrt%284-x%5E2%29
and for the bottom half
y=-sqrt%284-x%5E2%29