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If alpha+beta+gamma=2pi, prove that : co...

If `alpha+beta+gamma=2pi`, prove that : `cos^2 alpha + cos^2 beta + cos^2 gamma-2cosalpha cosbeta cosgamma=1`.

A

`1+ 2 sin alpha sin beta sin gamma`

B

`1+2 cos alpha cos beta cos gamma`

C

`1-sin alpha sin beta cos gamma`

D

`1-cos alpha cos beta cos gamma `

Text Solution

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The correct Answer is:
B
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ML KHANNA-TRIGONOMETRY RATIOS AND IDENTITIES-PROBLEM SET (6) ( MULTIPLE CHOICE QUESTIONS)
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  3. If alpha+beta+gamma=2pi, prove that : cos^2 alpha + cos^2 beta + cos^2...

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