Q.

Consider two circles C1:x2+y2=25 and C2:(xα)2+y2=16, where α(5,9). Let the angle between the two radii (one to each circle) drawn from one of the intersection points of C1 and C2 be sin1(638). If the length of common chord of C1 and C2 is β, then the value of (αβ)2 equals __________.          [2024]


Ans.

(1575)

We have,

C1 : x2+y2=25  or  C2 : (xα)2+y2=16

Let θ be the angle between two radii

 θ=sin1638

 sinθ=638

Area of OAB=12×4×5sinθ

 12×α×β2=10638  αβ=563  (αβ)2=1575.