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Prove that (i) " sin " .(pi)/(6). " co...

Prove that `(i) " sin " .(pi)/(6). " cos " .(pi)/(6) = (sqrt(3))/(4) " " (iii) cos^(2) .(pi)/(2) - sin^(2) .(pi)/(2) =(sqrt(3))/(2)`

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`(i) " sin " .(pi)/(6) " cos " .(pi)/(6) = (1)/(2) (2 sin .(pi)/(6) " cos " .(pi)/(6))`
`=(1)/(2) xx " sin " (2 xx (pi)/(6))`
`=(1)/(2) " sin " .(pi)/(3) = ((1)/(2) xx (sqrt(3))/(2))= (sqrt(3))/(4)`
`(ii) cos^(2) .(pi)/(12) - sin^(2).(pi)/(12) = cos (2xx (pi)/(12)) `
`=cos .(pi)/(6)= (3)/(2)`
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