Q.

Let R be the rectangle given by the lines x=0,x=2,y=0 and y=5. Let A(α,0) and B(0,β),α∈[0,2] and β∈[0,5], be such that the line segment AB divides the area of the rectangle R in the ratio 4 : 1. Then, the midpoint of AB lies on a         [2023]

1 parabola  
2 hyperbola  
3 straight line  
4 circle  

Ans.

(2)

ar(APQRB)ar(∆OAB)=41

Let M be the mid-point of AB.

M(h,k)≡(α2, β2)

⇒10-12αβ12αβ=4  ⇒ 52αβ=10

⇒  αβ=4

⇒  (2h)(2k)=4

∴  Locus of M is xy=1, which is a hyperbola.