Show that `sin^(2) 12^(@)+ sin ^(2)21^(@)+ sin ^(2)39^(@)+ sin^(2)48^(@)=1+ sin^(2)9^(@)+ sin^(2)18^(@)`

2sin^(2)x + sin^(2)2x =2

2 sin 40^(@) sin 10^(@)=

In a triangle sin^(4)A + sin^(4)B + sin^(4)C = sin^(2)B sin^(2)C + 2sin^(2) C sin^(2)A + 2sin^(2)A sin^(2)B , then its angle A is equal to-

[sin^2 1^@ + sin^2 2^@ +sin^2 3^@ + ……………….. + sin^2 87^@ + sin^2 88^@ + sin^2 89^@] equals____

(sin^2 1^@ + sin^2 3^@ + sin^2 5^@ + ………………… + sin^2 85^@ + sin^2 87^@ + sin^2 89^@) equals____

(i) If in a triangle ABC, a^(4) + b^(4) +c^(4) - 2b^(2) c^(2) -2c^(2)a^(2)=0 , then show that, C=45^(@) or 135^(@) . (ii) In in a triangle ABC, sin^(4)A + sin^(4)B + sin^(4)C = sin^(2)B sin^(2)C + 2sin^(2) C sin^(2)A + 2sin^(2)A sin^(2)B , show that, one of the angles of the triangle is 30^(@) or 150^(@)

sin ^(2) 6x - sin ^(2) 4x = sin 2x sin 10x

(1-4 sin 10^(@) sin70^(@))/(2 sin 10^(@))=

Find the value of sin^(2)5^(@)+sin^(2)10^(@)+sin^(2)15^(@)+.............+sin^(2)90^(@) .

The valud of sin 12^(@) sin 48^(@) sin 54^(@) is equal to-