Question

sin20 sin 40 sin60 sin 80

Answer 1

sin20. sin 40. sin60. sin80 
= sin60[sin20.sin40.sin80] 
=sqrt3 / 2 [sin20.sin(60-20).sin(60+20)] 
=sqrt3 / 2 [sin 3(20)/4] 
= sqrt3 / 2 [sin 60/4] 
= sqrt3 / 2 [√3/2*4] 
=sqrt3 /2 * sqrt3 /8 
=3/16 

Answer 2

−0.4651249 is the answer of this question