Question 1042507
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I think this is the correct area for this, being as it has to do with graphs. I need help graphing a circle, 
but my graphing calculator refuses to let me equal the equation to 15 instead of Y. 
Could anyone please explain how to graph this: x^2+y^2=15 ? I know it seems very simple, but I'm stuck! 
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{{{x^2 + y^2}}} = 15


is the circle with the center at the origin of a coordinate system with the radius r = {{{sqrt(15)}}}.

In general, if you have an equation {{{(x-h)^2 + (y-k)^2}}} = {{{a}}}, it desrcibes a circle with the center at the point (h,k) and the radius of {{{sqrt(a)}}}.

You can express y = {{{sqrt(15-x^2)}}} from the equation.
May be, your calculator is able to plot these functions

y = {{{sqrt(15-x^2)}}}  and  y = -{{{sqrt(15-x^2)}}},

that represent the upper and the lower parts of the circle?
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