Let C­1 and C2 be Two Circles With C2 lying Inside C1. A Circle C lying Inside C1 touches C1 internally And C2 externally. Identify The Locus Of The Centre Of C.

P is a variable on the line y = 4. Tangents are drawn to the circle x² + y²= 4 from P to touch it at A and B. The perpendicular PAQB is completed. Find the equation of the locus of Q.

Find the condition on a, b, c such that two chords of the circle

                x² + y² – 2ax – 2by + a² + b² – c² = 0  

passing through the point (a, b + c) are bisected by the line y = x.  

Find the limiting points of the circles 

       (x² + y² + 2gx + c) + λ(x² + y² + 2fy + d) = 0

The circle x² + y² – 4x – 8y + 16 = 0 rolls up the tangent to it at  by 2 units, assuming the x-axis as horizontal, find the equation of the circle in the new position.  

Find the equation of the circle of minimum radius which contains the three circles 

                   x² – y² – 4y – 5 = 0 

               x² + y² + 12x + 4y + 31 = 0  

and         x² + y² + 6x + 12y + 36 = 0

Find the equation of the circle passing through (1, 0) and (0, 1) and having the smallest possible radius.

If the line x cos α + y sin α = p cuts the circle x² + y² = a² in M and N, then show that the circle, whose diameter is MN, is 

A line meets the co-ordinate axes at A and B. A circle is circumscribed about the triangle OAB. If the distance of the points A and B from the tangent at O, the origin, to the circle are m and n respectively, find the equation of the circle.

Tangents PQ, PR are drawn to the circle x² + y² = 36 from the point P(–8, 2) touching the circle at Q, R respectively. Find the equation of the circumcircle of the âˆ†PQR.

The circle x² + y² – 4x – 4y + 4 = 0 is inscribed in a triangle which has two of its sides along the co-ordinate axes. The locus of the circumcentre of the triangle is x + y – xy + k(x² + y²)^1/2 = 0. Find k.