
Mid point of PQ lies on x−y+1=0
22cosθ+α−22sinθ−5α−2+1=0
2cosθ+α−2sinθ+5α+2+2=0
cosθ−sinθ+3α+2=0 ...(1)
∵ Slope of PQ is −1
2cosθ−α2sinθ+5α+2=−1
2sinθ+5α+2=−2cosθ+α
sinθ+cosθ+2α+1=0 ...(2)
eliminate α from (1) and (2)
⇒cosθ+5sinθ=1 , θ∈[0,2π]
⇒5×2sin2θcos2θ=2sin22θ
∴sin2θ=0⇒cosθ=1
or
sin2θ=5⇒cosθ=−1312
Sum of all possible values of abscissa of point P is
=2×1+2(13−12)=132
∴ 13 times sum of all possible values of abscissa of point P is 2.