Parametric equation (1 Viewer)

[Chris100]

P and Q are the points with parameters p and q on the parabola x=2at, y=at².
There were a few questions leading up to what PS+QS was, S being the focus point;

Given that and PQ being a focal chord, show that .

I keep coming to this answer: .

please help

 

[RealiseNothing]

PQ is not necessarily a focal chord. Also if this was the case then which is not true for all

 

[Chris100]

Yeah sorry for not including all the info, the question says that PQ is a focal chord

UPDATED POST

 

[RealiseNothing]

Ah that makes more sense, now I get your answer. The textbook answers must be wrong.