Mathematics 9709 · AS & A Level · Coordinate geometry
Coordinate geometry — practice question
The circle is given by the equation $x^2 + y^2 + ax + by - 12 = 0$. The points $A(1, 1)$ and $B(2, -6)$ are located on the circle.
(a)[4]
Determine the values of $a$ and $b$ and then use them to find the coordinates of the circle’s centre.
(b)[4]
Find the equation of the tangent to the circle at the point $A$, giving your answer in the form $px + qy = k$, where $p$, $q$ and $k$ are integers.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Writes down the equations $a+b=10$ and $2a-6b=-28$.” …