The circle C C\,C has the equation x2+y2+8x−4y+k=0x^2 + y^2 + 8x - 4y + k = 0x2+y2+8x−4y+k=0 where k k\,k is a constant. Given that the point (1,5)(1, 5)(1,5) lies on CCC.
Find the value of kkk.
Find the coordinates of the centre and the radius of CCC.
A straight line that passes through the point A(3,7)A(3, 7)A(3,7) is a tangent to the circle C C\,C at the point BBB. Find the exact length of the line ABABAB.
Practise AQA A Level Maths 1.6 C: Coordinate geometry in the (x, y) plane with exam-style questions for A Level Maths. 110 questions covering 1.6.1 Equation of a straight line, 1.6.2 Coordinate geometry of the circle, 1.6.3 Parametric equations of curves (A-level only), and 1.6.4 Parametric equations in modelling (A-level only), matched to the AQA A Level Maths (7357) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.