(a)[4]
Taking the tangent as $y = mx + 10$, determine the two values that $m$ can take.
(b)[3]
Determine the coordinates of $B$ and $C$.
(c)[3]
Point $D$ is the place where the circle meets the positive $x$-axis. Find angle $BDC$ in degrees.
Mathematics 9709 · AS & A Level · Coordinate geometry
Coordinate geometry — practice question
The diagram represents the circle whose equation is $x^2 + y^2 = 20$. The tangents that touch the circle at $B$ and $C$ go through $A(0, 10)$.