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(B) Let the line passing through $M(a, b)$ have an angle of inclination $	heta$.The parametric equations of the line are $x = a + r \cos 	heta$ and

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$a^2+b^2-k^2$

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(B) Let the line passing through $M(a, b)$ have an angle of inclination $	heta$.The parametric equations of the line are $x = a + r \cos 	heta$ and $y = b + r \sin 	heta$,where $r$ is the distance from $M$.Substituting these into the circle equation $x^2 + y^2 = k^2$:$(a + r \cos 	heta)^2 + (b + r \sin 	heta)^2 = k^2$$a^2 + 2ar \cos 	heta + r^2 \cos^2 	heta + b^2 + 2br \sin 	heta + r^2 \sin^2 	heta = k^2$$r^2 + 2r(a \cos 	heta + b \sin 	heta) + (a^2 + b^2 - k^2) = 0$This is a quadratic equation in $r$ whose roots $r_1$ and $r_2$ represent the distances $MC$ and $MD$.The product of the roots $r_1 \cdot r_2$ is given by the constant term of the quadratic equation.Therefore,$MC 	imes MD = a^2 + b^2 - k^2$.

If a line drawn from a fixed point $M(a, b)$ cuts the circle $x^2+y^2=k^2$ at $C$ and $D$,then $MC \times MD$ is equal to

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