`cos(pi/8)cos((3pi)/8)cos((5pi)/8)cos((7pi)/8)=`

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

Solve cos(pi/9)+cos(pi/3)+cos((5pi)/(9))+cos((7pi)/(9)) ?

Prove that cos((pi)/(8))+cos((3 pi)/(8))+cos((5 pi)/(8))+cos((7 pi)/(8))=0

Prove that cos^(4)pi/8+cos^(4)(3pi)/(8)+cos^(4)(5pi)/8+cos^(4)(7pi)/8=3/2

Statement I : sin^2pi/8+sin^2(3pi)/8+sin^2(5pi)/8+sin^2(7pi)/8=2 Statement II cos^2pi/8+cos^2(3pi )/8+cos^2(5pi)/8+cos^2(7pi/8)=2 Statement III: sin^2pi/8+sin^(3pi)/8+sin^2(5pi)/8sin^2 (7pi)/8=3/2

Evaluate: (1+cos(pi/8))(1+cos(3pi/8))(1+cos(5pi/8))(1+cos (7pi/8))

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

The value of cos((pi)/(4))*cos((pi)/(8))*cos((pi)/(16))cos((pi)/(2^(n))) equals

2sin((pi)/8)sin((2pi)/8)sin((3pi)/8)sin((5pi)/8)sin((6pi)/8)sin((7pi)/8) = ?