`cospi/5+cos(2pi)/5+cos(6pi)/5+cos(7pi)/5=0`

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

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

Find the value of cospi/7+cos(2pi)/7+cos(3pi)/7+cos(4pi)/7+cos(5pi)/7+cos(6pi)/+cos(7pi)/7

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

Prove: cos(pi/15)cos((2pi)/15)cos((3pi)/15)cos((4pi)/15)cos((5pi)/15)cos((6pi)/15)cos((7pi)/15) = 1/2^7

Show that cos(pi/15)cos((2pi)/15)cos((3pi)/15)cos((4pi)/15)cos((5pi)/15)cos((6pi)/15)cos((7pi)/15) = 1/2^7

If the value of "cos"pi/15"cos"(2pi)/15"cos"(3pi)/15"cos"(4pi)/15"cos"(5pi)/15"cos"(6pi)/15"cos"(7pi)/15 is (1)/(2^(k)) , then which of the following is true ?

The value of cos(pi/15)cos(2pi/15)cos(3pi/15)cos(4pi/15)cos(5pi/15)cos(6pi/15)cos(7pi/15) is eqaul to

cos20^0+cos80^0-sqrt(3)cos50^0 p. -1 cos0^0+cospi/7+cos(2pi)/7+cos(3pi)/7+cos(4pi)/7+cos(5pi)/7+cos(6pi)/7 q. -3/4 cos20^0+cos40^0+cos60^0-4cos10^0cos20^0cos30^0 r. 1 cos20^0cos100^0+cos100^0cos140^0-cos140^0cos200^0 s. 0

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