If the point P(α2,α) lies in the region corresponding to the acute angle between the lines x−3y=0 and x−5y=0 then
α∈(5,15)
α∈(5,8)
α∈(4,8)
α∈(3,5)
P lies in the acute angle
⇒α2−3α>0 and α2−5α<0
⇒α∈(−∞,0)∪(3,∞) and α∈(0,5)
∴α∈(3,5)