Prove that 1+ cos 2x + cos 4x + cos 6x = 4cosx cos2x cos 3x.
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Answered by
2
Answer:
Step-by-step explanation:
1 + Cos2A = 2cos^2(A)
Cos A + cos B = 2cos ((A +B)/2) cos( (A - B )/2)
Hence 2cos^2(x) + 2 cos (4x+6x)/2 cos (4x - 6x)/2
= 2cos^2(x) + 2cos5x cosx
= 2cosx (cosx + cos 5x)
= 2cosx ( 2cos 3x cos2x)
= 4cosx cos 2x cos2x
Hence proved
Answered by
1
Answer:
Mark as brainliest answer.
Step-by-step explanation:
Answer is in attachment in figure.
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