2.Prove that `cos50^(@)cos10^(@)-sin50^(@)sin10^(@)=(1)/(2)`

Prove that: (cos40^(@)+cos50^(@))/(sin40^(@)+sin50^(@))=1

sin 10 ^(@) sin 50^(@) sin 70^(@) = (1)/(8).

Prove that sin10^(@) sin 30^(@) sin 50^(@) sin 70^(@)=1/16

sin10 5^(@)+cos10 5^(@)=

i) Prove that: cos^(3)2A+3cos2A = 4(cos^(6)A-sin^(6)A) ii) Prove that: 4(cos^(3)10^(@) + sin^(3)20^(@)) = 3(cos10^(@)+sin20^(@))

Prove that: i) sin50^(@)-sin70^(@)+sin10^(@)=0 ii) sin(60^(@)+A)+sin(60^(@)-A) = sqrt(3)cosA

The value of sin50^(@)-sin70^(@)+sin10^(@) is

Prove that : sin 10^(@) + sin 20^(@) + sin 40^(@) + sin 50^(@) = sin 70^(@) + sin 80^(@).

Prove that cos^(4)A-sin^(4)A=cos^(2)A-sin^(2)A .

Evaluate : sin50^(@)cos40^(@)+cos40^(@)+cos50^(@)sin40^(@)