The circle C C\,C has centre (5,k)(5, k)(5,k), where k k\,k is a constant. The line y=2x+1y = 2x + 1y=2x+1 is a tangent to the circle CCC, touching C C\,C at the point A(3,7)A(3, 7)A(3,7).
Find an equation for CCC.
67 exam-style questions on CCEA A Level Maths 1.2 Co-ordinate geometry in the x, y plane, covering 1.2.1 Co-ordinate geometry in the x, y plane, 1.2.2 Co-ordinate geometry in the x, y plane, 1.2.3 Co-ordinate geometry in the x, y plane, 1.2.4 Co-ordinate geometry in the x, y plane, 1.2.5 Co-ordinate geometry in the x, y plane, 1.2.6 Co-ordinate geometry in the x, y plane, 1.2.7 Co-ordinate geometry in the x, y plane, and 1.2 Co-ordinate geometry in the x, y plane. Each one has a worked solution and a mark scheme showing where the marks go.