" (1) "cos70^(@)*cos10^(@)+sin70^(@)*sin10^(@)=(1)/(2)

Show that: cos70^(@)*cos10^(0)+sin70^(@)*sin10^(@)=(1)/(2)

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))

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

cos70^(@)+sin40^(@)=

cos70^(@)+sin40^(@)=

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

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

Prove that : (i) sin42^(@)cos48^(@)+sin48^(@)cos42^(@)=1 (ii) cos70^(@)cos20^(@)-sin70^(@)sin20^(@)=0

Prove that : (i) sin42^(@)cos48^(@)+sin48^(@)cos42^(@)=1 (ii) cos70^(@)cos20^(@)-sin70^(@)sin20^(@)=0