The ends of a line segment are P(1,3) and Q(1,1). R is a point on line segment PQ such that PR:QR=1:λ. If R is an interior point of parabola y2=4x, then
Let the coordinates of R be (α,β).
α=λ(1)+1λ+1=1, β=3λ+1λ+1
For R to be an interior point of the given parabola y2=4x,
β2−4α<0
⇒(3λ+1λ+1)2−4<0
⇒(3λ+1λ+1+2)(3λ+1λ+1−2)<0
⇒(5λ+3)(λ−1)<0
⇒−35<λ<1
But λ>0 ( ∵R is a point on the line segment PQ)
Hence, λ∈(0,1)
Hence, option A.