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If A+B+C=(pi)/(2) ,prove that: (i)cos^...

If A+B+C=`(pi)/(2)` ,prove that:
(i)`cos^(2)A+cos^(2)B+cos^(2)C=2+2"sin"A "sin"B "sin"C`
(ii)`"sin"^(2)+"sin"^(2)B+"sin"^(2)C=1-2 "sin"A sin B sin C`.

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