Question
Question: If w is a cube root of unity, then (3 + 5w + 3w<sup>2</sup>)<sup>2</sup> + (3 + 3w + 5w<sup>2</sup>...
If w is a cube root of unity, then
(3 + 5w + 3w2)2 + (3 + 3w + 5w2)2 is equal to –
A
4
B
0
C
– 4
D
None of these
Answer
– 4
Explanation
Solution
Sol. (3 (– w) + 5w)2 + (3 (– w2)+ 5w2)2
= (2w)2 + (2w2)2 = 4w2 + 4w = 4 (– 1) = – 4