Mark the Correct alternative in the following:
If x + i y = (1 + i) (1 + 2 i) (1 + 3i), then x2 + y2 =
Given that (1 + i) (1 + 2i) (1 + 3i) = x + i y …(1)
We can also say that
(1 - i) (1 - 2i) (1 - 3i) = x - i y …(2)
Multiply and divide the eq no. 2 with eq no. 1
((1)2 – (i)2)((1)2 – (2i)2)((1)2 – (3i)2) = ((x)2 – (iy)2)
x2 + y2 = 2 × 5 × 10 = 100
1