" The value of "cos(pi)/(7)cos(2 pi)/(7)cos(3 pi)/(7)" is "

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

The value of cos (2 pi)/(7)+cos (4 pi)/(7)+cos (6 pi)/(7) is

Find the value of cos(2 pi)/(7)+cos(4 pi)/(7)+cos(6 pi)/(7)

The value of cos""(pi)/(7)+cos""(2pi)/(7)cos""(3pi)/(7)+cos""(4pi)/(7)+cos""(5pi)/(7)+cos""(6pi)/(7)+cos""(7pi)/(7) is

The value of cos (pi)/(7) . cos (2 pi)/(7) . cos (4 pi)/(7) is

The value of cos((2pi)/7)cos((4pi)/7)cos((6pi)/7) is

cos(pi/7)cos((2pi)/7)cos((4pi)/7)=

Find the value of (cos(2 pi))/(7)(cos(4 pi))/(7)(cos(6 pi))/(7)

The value of cos ""pi/7 cos ""(2pi)/(7) cos ""(3pi)/(7) is-