Q.

Let the curve z(1+i)+z¯(1i)=4, zC, divide the region |z3|1 into two parts of area α and β. Then |αβ| equals :          [2025]

1 1+π3  
2 1+π6  
3 1+π4  
4 1+π2  

Ans.

(4)

Let z = x + iy, then from given equation, we have

(x + iy)(1 + i) + (xiy)(1 – i) = 4

 x + ix + iyy + xixiyy = 4

 2x – 2y = 4  xy = 2

Now, |z3|1  (x3)2+y21

β = Area of shaded region = π(1)2412×1×1

                                           = (π412) sq. units

α = Area of unshaded region inside the circle

   =34π(1)2+12×1×1=(3π4+12) sq. units

 Now, |αβ| = difference of area

 = (3π4+12)(π412)=π2+1.