If the two normals at $t_1$ and $t_2$ on parabola $y^2=4ax$ meet the parabola again at $t_3$ then $t_1t_2=$:
a)1
b)-1
c)2
d)-2

Question

experimentx · Answer

t1 and t2 are values of x or y?

ujjwal · Answer

I guess something parametric.. Not very sure.. It has something to do with parametric equations!

turingtest · Answer

usually you are given formulas for x and y in terms of t in these situations.
are you sure you haven't omitted any info from the question?

ujjwal · Answer

I am 100% sure i haven't omitted anything..

anonymous · Answer

parametric eqs for y^2 = 4ax will be x = 2at and y = at^2.....this is the standard form.

ujjwal · Answer

exactly! but i don't know how to proceed.. :(

anonymous · Answer

oh I'm sorry....I gave the parametric eqs wrong...it should be x = at^2 and y = 2at.

ujjwal · Answer

Did you?? LOL.. I didn't even read them.. I am reading your answer right now.

anonymous · Answer

yea...my bad! just realized i wrote them the other way round!

experimentx · Answer

let y=t, x=t^2/4a, ... |dw:1341948267556:dw|
perhaps