Q. An ellipse in the first quadrant is tangent to co-ordinate axes. If one focus is $F _1(3,7)$, and the other focus is $F_2(d, 7)$, then the value of $\sqrt{3 d}$ is equal to
Conic Sections
Solution:
We have $q _1 q _2=3 d = b ^2$
and $p_1 p_2=49=b^2$
Hence $3 d =49 \Rightarrow \sqrt{3 d }=\sqrt{49}=7$
