Question

sin(pi/5)sin(2pi/5)sin(3pi/5)sin(4pie/5)

Answer 1

LHS=sin(π5)sin(2π5)sin(π−2π5)sin(π−π5)

=sin(π5)sin(2π5)sin(2π5)sin(π5)

=sin2(π5)sin2(2π5)

=(sin(π5)sin(2π5))2

=((√10−2√54)(√10+2√54))2

=100−20256=80256=516

Proved

i hope it might help u