0 votes
105 views
in Complex Numbers by (98.9k points)
edited

If ω is a complex cube root of unity, prove that (1 – ω + ω2)6 + (1 + ω – ω2)6 = 128.

1 Answer

0 votes
by (98.9k points)
selected by
 
Best answer

ω is the complex cube root of unity.
∴ ω3 = 1 and 1 + ω + ω2 = 0
Also, 1 + ω2 = -ω, 1 + ω = -ω2
∴ L.H.S. = (1 – ω + ω2)6 + (1 + ω – ω2)6
= [(1 + ω2) – ω]6 + [(1 + ω) – ω2]6
= (-ω – ω))6 + (-ω2 – ω2)6
= (-2ω)6 + (-2ω2)6
= 64ω6 + 64ω12
= 64(ω3)2 + 64(ω3)4
= 64(1)2 + 64(1)4
= 128
= R.H.S.

Related questions

0 votes
1 answer 106 views
0 votes
0 answers 51 views
asked Sep 11, 2022 in Complex Numbers by Doubtly (98.9k points)
0 votes
1 answer 91 views
asked Sep 11, 2022 in Complex Numbers by Doubtly (98.9k points)
0 votes
1 answer 84 views
asked Sep 11, 2022 in Complex Numbers by Doubtly (98.9k points)

Doubtly is an online community for engineering students, offering:

  • Free viva questions PDFs
  • Previous year question papers (PYQs)
  • Academic doubt solutions
  • Expert-guided solutions

Get the pro version for free by logging in!

5.7k questions

5.1k answers

108 comments

557 users

...