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If a=cos 2alpha+i sin 2alpha, b =cos 2be...

If `a=cos 2alpha+i sin 2alpha, b =cos 2beta+i sin 2beta and c = cos 2gamma+i sin 2gamma`. Prove that.
(i) `sqrt(abc)+(1)/(sqrt(abc))=2cos(alpha+beta+gamma)`
(ii) `((a^(2)b^(2)+c^(2)))/(abc)=2cos2(alpha+beta-gamma)`

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