`cos(pi/7)*cos((2pi)/7)* cos((3pi)/7)`=

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

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

Select and write the correct answer from the given alternatives in each of the following: cos (pi/7) .cos ((2pi)/7).cos((4pi)/7)=

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

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

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

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

If cos(pi/7), cos((3pi)/7), cos((5pi)/7) are the roots of the equation 8x^3-4x^2-4x+1=0 The value of sec(pi/7)+sec((3pi)/7)+sec((5pi)/7) is

Prove that cos((2pi)/7)+cos((4pi)/7)+cos((6pi)/7)=-1/2