" (i) "cos60^(@)=1-2sin^(2)30^(@)=2cos^(2)30^(@)~~1" (ii) "

cos^(2)30^@-sin^(2)30^@=cos60^@

sin^(2)30+cos^(2)60

Prove that cos 60^(@)=cos^(2)30^(@)-sin^(2)30^(@) .

Prove that : cos^(2)30^(@)-sin^(2)30^(@)=cos60^(@)

Prove that : cos^(2)30^(@)-sin^(2)30^(@)=cos60^(@)

Verify each of the following : (i) sin60^(@)cos30^(@)-cos60^(@)sin30^(@)=sin30^(@) (ii) cos60^(@)cos30^(@)+sin60^(@)sin30^(@)=cos30^(@) (iii) 2sin 30^(@)cos30^(@)=sin60^(@) (iv) 2sin45^(@)cos45^(@)=sin90^(@)

"(1) "sin60^(@)cos30^(@)+sin30^(@)cos60^(@)

Verify that : sin60^(@)=2sin30^(@)cos30^(@)

Prove that : (i) sin 60^(@) = 2 sin 30^(@) cos 30^(@) (ii) 4(sin^(4) 30^(@) + cos^(4) 60^(@)) - 3(cos^(2)45 - sin^(2)90^(@)) = 2

Show that : cos^(2)60^(@)-sin^(2)60^(@)=-sin30^(@)