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The value of cos^2 48^0-sin^2 12^0 is (s...

The value of `cos^2 48^0-sin^2 12^0` is `(sqrt(5)+1)/8` (b) `(sqrt(5)-1)/8` (c) `(sqrt(5)+1)/5` (d) `(sqrt(5)+1)/(2sqrt(2))`

Text Solution

Verified by Experts

LHS `=cos^(2)48^(@)-sin^(2)12^(@)`
`=cos(48^(@)+12^(@))cos(48^(@)-12^(@))`
`=cos60^(@)cos36^(@)`
`=1/2 xx (sqrt(5)+1)/(8)=`RHS Hence Proved.
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