" (i) "sin2A=2sin A cos A

If A= 45^(@) , verify that: (i) sin 2A=2 sin A cos A (ii) cos 2A= cos^(2)A-"sin"^(2)A .

Prove that (1)sin2A=2sin A cos A(2)cos2A=cos^(2)A-sin^(2)A

If A = 30^(@) , then Prove that : (i) sin 2A = 2 sin A cos A = (2 tan A)/(1 + tan^(2)A) (ii) 2 cos^(2)A - 1 = 1 - 2 sin^(2) A

If A= 45^@ , verify that : sin 2A =2 sin A cos A .

If A=30^(@), prove that sin2A=2sin A cos A=(2tan A)/(1+tan^(2)A)

if sin2A=2sin A cos A and sin20^(@)=K then the value of cos20^(@)cos40^(@)cos80^(@)cos160^(@)-

Prove vectorially that sin 2A= 2 sin A *cos A .

If A + B + C =180^@ , prove that : sin^2 A- sin^2 B+ sin^2 C=2 sin A cos B sinC .

Prove that in a triangle ABC , sin^(2)A - sin^(2)B + sin^(2)C = 2sin A *cos B *sin C .

sin ^ (2) A + sin ^ (2) (AB) -2sin A cos B sin (AB) = sin ^ (2) B