Q.

ABCD is a square of side length 2 units. C1 is the circle touching all the sides of the square ABCD and C2 is the circumcircle of square ABCD. L is a fixed line in the same plane.                       [2006]

Q.    If P is any point of C1 and Q is another point on C2, then PA2+PB2+PC2+PD2QA2+QB2+QC2+QD2 is equal to

1 0.75  
2 1.25  
3 1  
4 0.5  

Ans.

(1)

According to the given question, we can assume the square ABCD with its vertices A(1,1), B(-1,1), C(-1,-1), D(1,-1).

P be the point (0,1) and Q be the point (2,0).

Then, PA2+PB2+PC2+PD2QA2+QB2+QC2+QD2

=1+1+5+52[(2-1)2+1]+2[(2+1)2+1]

=1216=0.75