I did too.(Original post by anshul95)
Well following the suggestions you should get a quadratic with distance squared on one side and a +ve coefficient of x^2 quadratic on the other side. Differentiate (don't bother to square root the answer and differentiate). Then set the derivative equal to zero. Substitute the value for x found into the expression for distance squared. Square root this value and voila!!
(When I did M1 I noticed these type questions come up a lot with vectors)
I thought I was connected with vectors so I tried to find the perpendicular foot.
This' my friend's question.
Ohmg, I've forgotten a lot
...Should I go back to school?