Home
Class 11
MATHS
Show that (1+ cos. (pi)/(8))(1+cos. (3pi...

Show that `(1+ cos. (pi)/(8))(1+cos. (3pi)/(8))(1+ cos. (5pi)/(8))(1+ cos .(7pi)/(8))=(1)/(8)`

A

`1/2`

B

`1/4`

C

`1/8`

D

`1/16`

Text Solution

Verified by Experts

The correct Answer is:
C
Promotional Banner

Topper's Solved these Questions

  • MULTIPLE & SUBMULTIPLE ANGLES

    AAKASH SERIES|Exercise EXERCISE-II|52 Videos

  • MULTIPLE & SUBMULTIPLE

    AAKASH SERIES|Exercise PRACTICE SHEET (EXERCISE - II) (LEVEL - II) (Linked Comprehension Type Questions)|5 Videos

  • MULTIPLE PRODUCT OF VECTORS

    AAKASH SERIES|Exercise PRACTICE EXERCISE|62 Videos

Similar Questions

Explore conceptually related problems

cos. (pi)/(13) + cos. (5pi)/(13) + cos. (8pi)/(13) + cos. (12pi)/(13)=

cos. (3pi)/(19) + cos . (7pi)/(19) + cos. (12pi)/(19) + cos. (16pi)/(19) =

Prove that: (1+ cos ""(pi)/(10)) (1+ cos ""(3pi)/(10)) (1+ cos ""(7 pi)/(10)) (1+ cos""(9 pi)/(10))=(1)/(16)

Prove that cos ^(2). (pi)/(8) + cos ^(2). (3pi)/(8)+ cos ^(2). (5 pi )/(8)+ cos ^(2). (7 pi)/(8)=2

((1 + "cos"(pi)/(8) -i "sin"(pi)/(8))/(1 + "cos"(pi)/(8) + i "sin" (pi)/(8)))^(12)=

Prove that cos. (2pi)/(7). Cos. (4pi)/(7). Cos. (8pi)/(7)=(1)/(8)

If A is not an integral multiple of (pi) , prove that cos A cos 2A cos 4A cos 8A =(sin 16A)/(16 sin A) Hence deduce that cos. (2pi)/(15). Cos. (4pi)/(15) .cos. (8pi)/(18). Cos. (16pi)/(15)=(1)/(16)

AAKASH SERIES-MULTIPLE & SUBMULTIPLE ANGLES-PRACTICE EXERCISE
  1. If 4 sin(60^(@) + theta ) sin (60^(@) - theta )-1=k cos 2 theta , th...

    Text Solution

    |

  2. cos6^(@) cos42^(@) cos66^(@) cos78^(@) =

    Text Solution

    |

  3. Show that sin""(pi)/5.sin""(2pi)/5.sin""(3pi)/5.sin""(4pi)/5=5/16.

    Text Solution

    |

  4. cos (pi/7) cos ((2pi)/(7) ) cos ( (4pi )/(7) ) =

    Text Solution

    |

  5. "sin"pi/14" sin"(3pi)/14" sin"(5pi)/14" sin"(7pi)/5=

    Text Solution

    |

  6. "sin"^(2)pi/8" + sin"^(2)(3pi)/8" + sin"^(2)(5pi)/8" + sin"^(2)(7pi)/8...

    Text Solution

    |

  7. "sin"^(4)pi/8" +sin"^(4)(3pi)/8" +sin"^(4)(5pi)/8" +sin"^(4)(7pi)/8=

    Text Solution

    |

  8. Show that (1+ cos. (pi)/(8))(1+cos. (3pi)/(8))(1+ cos. (5pi)/(8))(1+ c...

    Text Solution

    |

  9. If A=2 sin^(2) theta - cos 2 theta , then

    Text Solution

    |

  10. If x+y+z =xyz, then sum(2x)/(1-x^(2))=

    Text Solution

    |

  11. If xy+yz+zx=1 , then sum(x+y)/(1-xy)=

    Text Solution

    |

  12. If sqrt(1+sinA)+sqrt(1-sinA)=2"sin"A/2" then"A/2 in

    Text Solution

    |

  13. If A=340^(@) then 2 sin A//2=

    Text Solution

    |

  14. I : If 180^(@) lt theta lt 270^@ , sin theta = -3//5 " then " cos the...

    Text Solution

    |

  15. If A=cos^(2)10^(@)+cos^(2)50^(@)+cos^(2)70^(@), B="sin"^(4)(3pi)/8-"...

    Text Solution

    |

  16. If A=(2sinx)/(sin3x)+(tanx)/(tan3x), B=cos10^(@)cos30^(@)cos50^(@)cos...

    Text Solution

    |

  17. Assertion (A): tantheta+2tan2theta+4tan4theta+8tan8theta+16cot16theta=...

    Text Solution

    |

  18. Assertion (A): cos^(3)x+cos^(3)(120^(@)+x)+cos^(3)(120^(@)-x)=3/4cos3x...

    Text Solution

    |

  19. If 0ltxltpi and cosx+sinx=1/2 then tanx=

    Text Solution

    |

  20. If A=sin^(2) theta + cos^(4) theta , then for all values of theta ,...

    Text Solution

    |