Home
Class 12
MATHS
2cos(pi/13)cos(9pi/13)+cos(3pi/13)+cos(5...

`2cos(pi/13)cos(9pi/13)+cos(3pi/13)+cos(5pi/13)=0`

A

0

B

`-1`

C

1

D

2

Text Solution

Verified by Experts

The correct Answer is:
A
Promotional Banner

Topper's Solved these Questions

  • TRIGNOMETRIC FUNCTIONS

    AAKASH INSTITUTE|Exercise Assignment Section-B (Objective Type Questions (One option is correct))|1 Videos

  • TRIGNOMETRIC FUNCTIONS

    AAKASH INSTITUTE|Exercise Section-B (Objective Type Questions One option is correct)|131 Videos

  • TRIGNOMETRIC FUNCTIONS

    AAKASH INSTITUTE|Exercise Try Yourself|32 Videos

  • THREE DIMENSIONAL GEOMETRY

    AAKASH INSTITUTE|Exercise ASSIGNMENT SECTION - J|10 Videos

  • VECTOR ALGEBRA

    AAKASH INSTITUTE|Exercise SECTION-J (Aakash Challengers Questions)|5 Videos

Similar Questions

Explore conceptually related problems

Prove that: 2cos (pi)/(13) cos (9 pi)/(13)(3 pi)/(13)(5 pi)/(13)=0

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

cos^(-1)(cos(13pi/6))

What is the value of cos(pi//9)+cos(pi//3)+cos(5pi//9)+cos(7pi//9) ?

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

The expression (cos(10 pi))/(13)+(cos(8 pi))/(13)+(cos(3 pi))/(13)+(cos(5 pi))/(13)

AAKASH INSTITUTE-TRIGNOMETRIC FUNCTIONS -Assignment section-A (Objective Type Questions (One option is correct))
  1. In a triangleABC, if sinA - cosB = cos C, then the measured of angleB ...

    Text Solution

    |

  2. The value of cos1^(@) cos 2^(@) ..............cos179^(@) is

    Text Solution

    |

  3. 2cos(pi/13)cos(9pi/13)+cos(3pi/13)+cos(5pi/13)=0

    Text Solution

    |

  4. If sintheta +costheta =1, then the value of sin2theta is equal to

    Text Solution

    |

  5. If tan A=1/2 and tan B=1/3, then tan(A +B) is equal to

    Text Solution

    |

  6. The minute hand of a watch is 3cm long. How far does its tip move in 2...

    Text Solution

    |

  7. If sintheta=(-4)/(5) and theta lies in third quadrant, then the value...

    Text Solution

    |

  8. The value of tan75^(@) =

    Text Solution

    |

  9. If 1,omega , omega^2 are the cube roots of unity , then Delta=|(1,ome...

    Text Solution

    |

  10. The value of 2sinA cos^(3)A -2sin^(3)A cosA is

    Text Solution

    |

  11. If tanalpha=(sqrt(3)+1)/(sqrt(3)-1), then the expression cos 2alpha +(...

    Text Solution

    |

  12. If sin^2 theta=1/4 , then the value of theta is

    Text Solution

    |

  13. The solution of the equation cos^2theta+sintheta+1=0 lies in the inter...

    Text Solution

    |

  14. The general solution of tan3x=1 is

    Text Solution

    |

  15. If sin theta =sqrt(3) cos theta, -pi lt theta lt 0, then the value of ...

    Text Solution

    |

  16. The total number of solutions of the equation tanx + secx = 2 which li...

    Text Solution

    |

  17. If the lengths of the sides of a triangle are 3, 5, 7, then its larges...

    Text Solution

    |

  18. sin^2 75^@-sin^2 15^@=

    Text Solution

    |

  19. If a cosA=b cosB, then triangleABC is

    Text Solution

    |

  20. If a=16, b=24 nad c=20, then the value of cos(B/2) is

    Text Solution

    |