Home
Class 12
MATHS
The value of cos""(pi)/(11)+cos""(3pi)/(...

The value of `cos""(pi)/(11)+cos""(3pi)/(11)+cos""(5pi)/(11)+cos""(7pi)/(11)+cos""(9pi)/(11),` is

A

`1/2`

B

1

C

`1/2`

D

none of these

Text Solution

Verified by Experts

The correct Answer is:
C
Promotional Banner

Topper's Solved these Questions

  • TRIGNOMETRIC RATIOS & IDENTITIES

    MOTION|Exercise Exercise 2(Level -I)|36 Videos

  • TRIGNOMETRIC RATIOS & IDENTITIES

    MOTION|Exercise Exercise -2(Level -II)|12 Videos

  • TRIGNOMETRIC RATIOS & IDENTITIES

    MOTION|Exercise Exercise -4(Level -II)|9 Videos

  • THREE DIMENSIONAL GEOMETRY (3 -D)

    MOTION|Exercise SOLVED EXAMPLE|33 Videos

  • TRIGONOMETRIC EQUATION

    MOTION|Exercise EXERCISE 4|10 Videos

Similar Questions

Explore conceptually related problems

The value of cos""(pi)/(9)cos""(2pi)/(9)cos""(3pi)/(9), is

The value of cos""(pi)/(9)cos""(2pi)/(9)cos""(3pi)/(9)cos""(4pi)/(9), is

The value of (cos pi)/(11)+(cos(3 pi))/(11)+(cos(5 pi))/(11)+(cos(7 pi))/(11)+(cos(9 pi))/(11)

cos(pi)/(11)+cos(3 pi)/(11)+cos(5 pi)/(11)+cos(7 pi)/(11)+cos(9 pi)/(11)=(1)/(2)

The value of 2"cos"(pi)/(13)"cos"(9pi)/(13)+"cos"(3pi)/(13)+"cos"(5pi)/(13) is

The value of 2(cos pi/11 + cos(3pi)/11 + cos(5pi)/11 + cos(7pi)/11 + cos(9pi)/11) is……….

The value of sin""(pi)/(14).sin""(3pi)/(14).sin""(5pi)/(14).sin""(7pi)/(14).sin""(9pi)/(14).sin""(11pi)/(14).sin""(13pi)/(14) is

MOTION-TRIGNOMETRIC RATIOS & IDENTITIES -Exercise 1
  1. The value of cos10^(@)-sin 10^(@) is

    Text Solution

    |

  2. If 0 lt x lt pi and cos x + sin x = 1/2, then tan x is

    Text Solution

    |

  3. If A lies in the third quadrant and 3 tan A-4 = 0, then 5 sin 2A + 3si...

    Text Solution

    |

  4. For -pi/2 lt theta lt pi/2 ,(sin theta + sin 2 theta)/(1+cos theta + c...

    Text Solution

    |

  5. Find the value of cos 12^(@)+cos 84^(@)+cos 156^(@)+cos 132^(@)

    Text Solution

    |

  6. Prove that cos 36^(@) cos 72^(@) cos 108^(@) cos 144^(@)=1//16.

    Text Solution

    |

  7. The value oif the expressin (1+cospi/10)(1+cos(3pi)/10)(1+cos(7pi)/10)...

    Text Solution

    |

  8. (cos 20^(@)+8 sin 70^(@) sin 50^(@) sin 10^(@))/( sin^(2)80^(@)) is eq...

    Text Solution

    |

  9. Which of the following is least ?

    Text Solution

    |

  10. Find the value of x for which f(x)=sqrt(sinx-cosx) is defined, x in [0...

    Text Solution

    |

  11. Find the number of solutions of sinx=x/(10)

    Text Solution

    |

  12. Number of solution of equation sin x = x^2 + x + 1 is

    Text Solution

    |

  13. Prove that the least positive value of x , satisfying tanx=x+1, lies i...

    Text Solution

    |

  14. If a sin^(2) x +b lies in the interval [-2,8] for every x in R then...

    Text Solution

    |

  15. Find the greatest value of c such that system of equation x^(2) + y^(...

    Text Solution

    |

  16. Given that sum(k=1)^35 sin5k^@ = tan(m/n)^@ , where m and n are relat...

    Text Solution

    |

  17. The value of cos""(pi)/(11)+cos""(3pi)/(11)+cos""(5pi)/(11)+cos""(7pi)...

    Text Solution

    |

  18. If tan alpha +cot alpha =a then the value of tan^(4) alpha +cot^(4) al...

    Text Solution

    |

  19. The number of real solutions of the equation sin(e^x)=2^x+2^(-x) is

    Text Solution

    |

  20. In a right angled triangle the hypotenuse is 2sqrt(2) times the perpen...

    Text Solution

    |