cos`50^(@)50`' cos `9^(@)10'-sin 50^(@)50' sin 9^(@)10`' = __________.

sin 50 ^(@) - sin 70^(@) + sin 10^(@)

sin 40^(@) - cos 50^(@)= _________

4cos^(3)40^(@)-3sin50^(@)=

(i) sin10^(@)sin50^(@)sin70^(@)

sin50 ^ (@) - sin70 ^ (@) + sin10 ^ (@) = 0

sin50^(@)-sin70^(@)+sin10^(@)=?

Prove that (i) sin 70^(@) cos 10^(@) -cos 70^(@) sin 10^(@) =(sqrt(3))/(2) (ii) cos 50^(@) cos 10^(@) -sin 50^(@) sin 10^(@) =(1)/(2) (ii) cos 80^(@) cos 20^(@) + sin 80^(@) sin 20^(@) =(1)/(2) (iv) sin 36^(@) cos 9^(@) + cos 36^(@) sin 9^(@) =(1)/(sqrt(3))

If cos 25^(@) + sin 25^(@) =p , then: cos 50^(@)=

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