cos(pi)/(7)cos(2 pi)/(7)*cos(3 pi)/(7)=(1)/(8)

Prove that: cos(pi)/(7)cos(2 pi)/(7)cos(4 pi)/(7)=-(1)/(8)

Prove that :(cos pi)/(7)(cos(2 pi))/(7)(cos(3 pi))/(7)(cos(4 pi))/(7)=(1)/(8)

prove that cos2(pi)/(7)+cos4(pi)/(7)+cos6(pi)/(7)=-(1)/(2)

Show that cos(pi/7)cos((2pi)/7)cos((3pi)/7)=1/8

Prove that : cos(pi/7)cos((2pi)/7) cos((3pi)/7)=1/8

The value of cos((pi)/(7))+cos((2 pi)/(7))+cos((3 pi)/(7))+cos((4 pi)/(7))+cos((5 pi)/(7))+cos((6 pi)/(7))+cos((7 pi)/(7)) is 1(b)-1(c)0(d) none of these

Prove that: cos(pi/7)cos((2pi)/7)cos((4pi)/7)=-1/8

3.Prove that (i) "cos((2pi)/7)*cos((4pi)/7)*cos((8pi)/7)=1/8

the value of (cos pi)/(7)cos(2(pi)/(7))cos(3(pi)/(7)) is

cos.(2pi)/(7)+cos.(4pi)/(7)+cos.(6pi)/(7)