Home
Class 12
MATHS
The value of cos (pi)/(7) . cos (2 pi)/(...

The value of `cos (pi)/(7) . cos (2 pi)/(7) . cos (4 pi)/(7)` is

A

`-(1)/(8)`

B

`-(1)/(4)`

C

`-(1)/(16)`

D

`-(3)/(16)`

Text Solution

Verified by Experts

Promotional Banner

Topper's Solved these Questions

  • MAXIMA AND MINIMA

    HIMALAYA PUBLICATION|Exercise QUESTION BANK|167 Videos

  • Pair Of Lines

    HIMALAYA PUBLICATION|Exercise QUESTION BANK|129 Videos

Similar Questions

Explore conceptually related problems

The value of cos (pi)/(5) . cos (2 pi)/(5). cos (4 pi)/(5) . cos (8 pi)/(5) is

The value of cos (2 pi)/(7)+cos (4 pi)/(7)+cos (6 pi)/(7) is

The value of sin (pi)/(7)+sin (2 pi)/(7)+sin (3 pi)/(7) is

The value of (1+cos (pi)/(8))(1+cos (3 pi)/(8))(1+cos (5 pi)/(8))(1+cos (7 pi)/(8)) is

The value of (sin (pi/3)+i cos (pi/3))^(3) is

One of the values of ((cos (pi)/(6)-i sin (pi)/(6))^(1 / 2))((cos (pi)/(6)+i sin (pi)/(6))^(1 / 2)) is

The product of the values of (cos ((pi)/(3))+i sin( (pi)/(3)))^(3 / 4) is

cos ^(2) (3 pi)/(5)+cos ^(2) (4 pi)/(5)=

Find the value of cos^(-1)(cos((13pi)/(6)))

HIMALAYA PUBLICATION-MEASUREMENT OF ANGLES, TRIGONOMETRIC RATIOS AND RELATION BETWEEN SIDES AND ANGLES OF A TRIANGLE-QUESTION BANK
  1. sin 12^(circ) .sin 48^(circ) .sin 54^(circ)=

    Text Solution

    |

  2. The value of sin 20^(circ) sin 40^(circ) sin 60^(circ) sin 80^(circ) i...

    Text Solution

    |

  3. The value of cos (pi)/(7) . cos (2 pi)/(7) . cos (4 pi)/(7) is

    Text Solution

    |

  4. cos 12^(circ)+cos 84^(circ)+cos 156^(circ)+cos 132^(circ)=

    Text Solution

    |

  5. cos (pi)/(11)+cos (3 pi)/(11)+cos (5 pi)/(11)+cos (7 pi)/(11)+cos (9 p...

    Text Solution

    |

  6. cos 20^(circ) cos 40^(circ) cos 60^(circ) cos 80^(circ)=

    Text Solution

    |

  7. The value of cos""pi/65.cos""(2pi)/65.cos""(4pi)/65.cos""(8pi)/65.cos"...

    Text Solution

    |

  8. sin 10^(circ) . sin 30^(circ) . sin 50^(circ) . sin 70^(circ)=

    Text Solution

    |

  9. The value of sin (pi)/(7)+sin (2 pi)/(7)+sin (3 pi)/(7) is

    Text Solution

    |

  10. In a triangle A B C, tan A+tan B+tan C=6 and tan A . tan B=2, then the...

    Text Solution

    |

  11. If A+B+C=pi, then cos B+cos C=

    Text Solution

    |

  12. If A+B+C=180^(circ) then the value of cot (A)/(2)+cot (B)/(2)+cot (C)/...

    Text Solution

    |

  13. If in a triangle A B C, tan A+tan B+tan C=6 then cot A . cot B . cot C...

    Text Solution

    |

  14. If A+B+C=pi, prove that sin 2A+sin 2B+sin 2C=4 sinA sin B sinC.

    Text Solution

    |

  15. If any triangle A B C sin ^(2) A+sin ^(2) B-sin ^(2) C=

    Text Solution

    |

  16. A tower subtends an angle alpha at a point on the same level as the fo...

    Text Solution

    |

  17. Two poles are 25 metres and 15 metres high and the line joining their ...

    Text Solution

    |

  18. The tops of two poles of height 20 mt and 14 mt are connected by a wir...

    Text Solution

    |

  19. The angle of elevation of the sun, if the length of the shadow of a to...

    Text Solution

    |

  20. If two towers of heights h(1) and h(2) subtend angles 60^(o) and 30^(c...

    Text Solution

    |