Prove that: `sin20^(@).sin40^(@)*sin60^(@).sin80^(@)=((3)/(16))^@`

Prove that: i) sin20^(@)sin40^(@)sin60^(@)sin80^(@)=3/16 ii) sin10^(@)sin50^(@)sin60^(@)sin70^(@)=sqrt(3)/16 iii) sin20^(@)sin40^(@)sin80^(@)=sqrt(3)/8

Prove that: sin6^(@)sin42^(@)sin66^(@)sin78^(@)=1/16

Prove that : cos30^(@).cos60^(@)-sin30^(@).sin60^(@)=0

Prove that : cos30^(@).cos60^(@)-sin30^(@).sin60^(@)=0

Prove that : sin60^(@)cos30^(@)+cos60^(@).sin30^(@)=1

Prove that : sin60^(@)=2sin30^(@)cos30^(@) .

Prove that : sin60^(@)=2sin30^(@)cos30^(@) .

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

Prove that sin20^(@)sin40^(@)sin80^(@)=(sqrt(3))/(8)

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