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Prove that cos(30^(@) -A ) cos (30^(@) +...

Prove that cos`(30^(@) -A ) cos (30^(@) + A ) + cos (45^(@) - A) cos (45^(@) + A) = cos 2A + (1)/(4)`.

Text Solution

Verified by Experts

The correct Answer is:
`cos 2A +1/4`
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