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

If the value of cos((2pi)/7) + cos((4pi)/7)+cos((6pi)/7)+cos((7pi)/7)=-l/2 Find the value of l

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

Find the value of 2cos^3(pi/7)-cos^2(pi/7)-cos(pi/7)

The value of cos((2pi)/7)cos((4pi)/7)cos((6pi)/7) is a. -1//2 b. \ 1//2 c. \ 1//4 d. 1//8

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 1 (b) -1 (c) 0 (d) none of these

Find the value of |{:(cos((2pi)/(63)),,cos((3pi)/(70)),,cos((4pi)/(77))),(cos((pi)/(72)),,cos((2pi)/(80)),,cos((3pi)/(88))),(1,,cos((pi)/(90)),,cos((2pi)/(99))):}|

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

The exact value of cos((2pi)/28)cosec((3pi)/28)+cos((6pi)/28)cosec((9pi)/28)+cos((18pi)/28)cosec((27pi)/28)

Find the value of cos^2pi/(16)+cos^2(3pi)/(16)+cos^2(5pi)/(16)+cos^2(7pi)/(16)dot

Find the value of cos^2. pi/16+cos^2. (3pi)/16+cos^2. (5pi)/16+cos^2. (7pi)/16 .