Question:
Let $A$ be a fixed point $(0,6)$ and $B$ be a moving point $(2 \mathrm{t}, 0)$. Let $\mathrm{M}$ be the mid-point of $\mathrm{AB}$ and the perpendicular bisector of $\mathrm{AB}$ meets the $\mathrm{y}$-axis at $\mathrm{C}$. The locus of the mid-point $\mathrm{P}$ of $\mathrm{MC}$ is:
Correct Option: , 3
Solution:
$\mathrm{A}(0,6)$ and $\mathrm{B}(2 \mathrm{t}, 0)$
Perpendicular bisector of $\mathrm{AB}$ is
$(y-3)=\frac{t}{3}(x-t)$
So, $\mathrm{C}=\left(0,3-\frac{\mathrm{t}^{2}}{3}\right)$
Let P be (h,k)
$\mathrm{h}=\frac{\mathrm{t}}{2} ; \mathrm{k}=\left(3-\frac{\mathrm{t}^{2}}{6}\right)$
$\Rightarrow \mathrm{k}=3-\frac{4 \mathrm{~h}^{2}}{6} \Rightarrow 2 \mathrm{x}^{2}+3 \mathrm{y}-9=0$ option (3)