Right now, I need to use the equation of a circle to describe a geometry I'm dealing with in a research project. For some reason, I cannot make sense of it, and it is extremely frustrating... Right now I'm using:(adsbygoogle = window.adsbygoogle || []).push({});

r = Rcos(theta)+sqrt(A^2-(Rsin(theta))^2)

where R is the distance from the origin to the center of the circle and A is the radius of the circle. Assume the center of the circle lies on the polar axis. I keep getting complex lengths for 'r', which obviously comes from the negative term in the square root. Can someone explain to me in a physical sense why this is happening? And my main question is how can I make it so I only obtain proper, real lengths for 'r'? Any help is appreciated

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# Equation of a circle

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