prelim math help (1 Viewer)

[Joshmosh2]

14. b) Find the equation of the focal chord through Q

We are given the information Q(2aq,aq^2) lies on the parabola, and x^2=4ay.

What I tried was to find the focal point of the parabola, and use gradient formula using those co-ordinates but I can't seem to solve it. Help please.

 

[Cleavage]

http://gyazo.com/73dced3e7dd17689cd60e6e608c6db0c

Out of curiosity, where did you get mixed up? A focal chord is simply a chord which passes through the focus of a parabola.

 

[Joshmosh2]

It didn't occur to me that I should simplify the gradient first, then sub into the eqn, because what i got was very tedious. Much better now!