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Show that : cos 60^(@)=2cos^(2)30^(@)-1...

Show that : `cos 60^(@)=2cos^(2)30^(@)-1`

Text Solution

Verified by Experts

L.H.S.`=cos60^(@)=(1)/(2)`
R.H.S. `=2cos^(2)30^(@)-1=2((sqrt(3))/(2))^(2)-1=(3)/(2)-1=(3-2)/(2)=(1)/(2)`
`:.`L.H.S. =R.H.S.
Therefore , `cos 60^(@)=2cos^(2)30^(@)-1`
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