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

cos""(pi)/(7)+cos""(2pi)/(7)+cos""(3pi)/(7)+......cos""(6pi)/(7)=?

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""(pi)/(11)+cos""(3pi)/(11)+cos""(5pi)/(11)+cos""(7pi)/(11)+cos""(9pi)/(11), is

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

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

the value of cos0+cos((pi)/(7))+cos(2(pi)/(7))+cos(3(pi)/(7))+cos(4(pi)/(7))+cos(5(pi)/(7))cos(6(pi)/(7)) is (i) (1)/(2)(ii)-(1)/(2)(iii)0(iv)1