show that `sin (2pi/7) + sin(4 pi/7) + sin (8 pi/7) = sqrt7/2`

Show that: sin((2pi)/7)+ sin ((4pi)/7) + sin( (8pi)/7) = sqrt7/2 .

show that sin (2 (pi) / (7)) + sin (4 (pi) / (7)) + sin (8 (pi) / (7)) = (sqrt (7)) / (2)

Show that : sin pi/7 *sin 2pi/7* sin3pi/7 = sqrt7/8

sin "" (2pi)/(7) + sin "" (4pi)/(7) + sin "" (8pi)/(7) =

Show that : "sin" 2(pi)/(7)+ "sin"(4pi)/(7)-"sin" (6pi)/(7) =4 "sin" (pi)/(7) "sin" (2pi)/(7) "sin" (3pi)/(7)

Prove that: sin ((pi)/(7))+sin((2pi)/(7)) + sin((8pi)/(7)) + sin((9pi)/(7))=0

the value of sin(pi/7)+sin((2pi)/7)+sin((3pi)/7) is