Arze:"The circle with center and radius touches externally the circle center radius . The tangent at their common point passes through the origin. Show that,

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Solutionfor(i)if they have a common point of (0,0), use the standard formula for circle:

(0 - A)^2 + (0 - B)^2 = R^2,

(0 - a)^2 + (0 - b)^2 = r^2,

subtract,

(A^2 - a^2) + (B^2 - b^2) = (R^2 - r^2)