Question

sin10*sin20*sin40*sin60

Answer 1

sin 20 .sin 40.sin60.sin 80 = 3/2 . sin 20 .sin (60 - 20) sin (60+20) = 3/2 . sin 20.(sin 2 60 - sin 2 20) = 3/2 .sin 20 . (3/4 - sin 2 20) = 3/8 .(3 sin 20 - 4 sin 3 20) = 3/8 .(sin 3 . 20) = 3/8 sin 60 = 3/16

Answer 2

DEAR STUDENT,

Kindly check the attached papers for a detailed solution along with step by step elaboration to reach our final solution that is our final desired or required answer to this query that is completely proved.

$\boxed{\bf{\underline{L.H.S. = R.H.S.}}}$

Which is the required proof or solution process for this type of query.

Hope this helps you and solves your doubts for applying trigonometric identifies to reach a proper solution or a proof!!!!!