Edexcel IALMathematicsGeneral Applications5 Marks
A circle C has equation x^2 + y^2 - 4x + 6y - 12 = 0. (a) Find the coordinates of the centre of C and the radius of C.
- (a)Find the coordinates of the centre of C and the radius of C.[5]
Mark scheme
Marking points from the official mark scheme. The mark or mark type is shown in brackets.
- M1 for attempting to complete the square for x terms: (x ± 2)^2 ... or for y terms: (y ± 3)^2 ...
- A1 for (x - 2)^2 and (y + 3)^2.
- M1 for using r^2 = g^2 + f^2 - c or rearranging the equation to find the value of r^2.
- A1 for centre (2, -3).
- A1 for radius = 5. (Must be the positive square root).
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