" The value of "cos(pi)/(5)cos(2 pi)/(5)cos(4 pi)/(5)cos(8 pi)/(5)" is : "

The value of cos(pi)/(5)cos.2(pi)/(5)cos4(pi)/(5)cos8(pi)/(5)=

cos(pi/5)cos((2pi)/5)cos((4pi)/5)cos((8pi)/5)=

The value of cos(pi)/(8)cos(3 pi)/(8)cos(5 pi)/(8)cos(7 pi)/(8) is equal to

Find the value of cos((2pi)/5).cos(pi/5)

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)/(11)+(cos(3 pi))/(11)+(cos(5 pi))/(11)+(cos(7 pi))/(11)+(cos(9 pi))/(11)

Prove that: (cos pi)/(5)(cos(2 pi))/(5)(cos(4 pi))/(5)(cos(8 pi))/(5)=(-1)/(6)

Prove that: cos(pi/5)cos((2pi)/5)cos((4pi)/5)cos((8pi)/5)=(-1)/16