Solution:
Let Z = ((1+i)/√2)2/3
= ((1/√2)+(i/√2))2/3
Z = (cos (π/4) + i sin (π/4))2/3
Z = cos (8k+1)π/6 + i sin (8k+1)π/6
Substitute k = 1, we get
Z = cos (8+1)π/6 + i sin (8+1)π/6
= cos 9π/6 + i sin 9π/6
= cos 3π/2 + i sin 3π/2
= 0-1(i)
= -i
Hence option (2) is the answer.