Prove that: `cos^(2)48^(@)-sin^(2)12^(@)=(sqrt(5)+1)/(8)`

1.	Prove that: `cos^(2)48^(@)-sin^(2)12^(@)=(sqrt(5)+1)/(8)`
Answer» 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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