Question
cos20.cos40.cos60.cos80=
Read 1 Solution.
cosθ.cos(60-θ).cos(60-θ)=1/4cos3θ
=1/4cos3.20.cos60
=1/4.1/2.1/2
=1/16
C NARENDRA CHARY 8 year ago
is this solution helpfull: 5 10
cos20.cos40.cos60.cos80=
cosθ.cos(60-θ).cos(60-θ)=1/4cos3θ
=1/4cos3.20.cos60
=1/4.1/2.1/2
=1/16