Home
Class 11
MATHS
Show that : cos9^@.cos18^@.cos36^@.cos72...

Show that : `cos9^@.cos18^@.cos36^@.cos72^@=(sin36^@)/(16cos81^@)`

Promotional Banner

Topper's Solved these Questions

  • TRIGONOMETRIC FUNCTIONS OF COMPOUND ANGLES AND FACTORIZATION FORMULAE

    MARVEL PUBLICATION|Exercise MCQs|101 Videos

  • TRIGONOMETRIC FUNCTIONS

    MARVEL PUBLICATION|Exercise MCQs|175 Videos

Similar Questions

Explore conceptually related problems

Prove that: cos36^(@)cos72^(@)cos108^(@)cos144^(@)=(1)/(16)

Prove that 4cos12^(@)cos48^(@)cos72^(@)=cos36^(@)

cos54^(@)cos36^(@)-sin54^(@)sin36^(@)=0

cos6^(@)*sin24^(@)*cos72^(@)=

The value of cos12^(@)cos24^(@)cos36^(@)cos48^(@)cos72^(@)cos84^(@), is

Prove that: i) cos10^(@)cos30^(@)cos50^(@)cos70^(@)=3/16 ii) cos20^(@)cos40^(@)cos60^(@)cos80^(@)=1/16 iii) 4cos12^(@)cos48^(@)cos72^(@)=cos36^(@) iv) cos40^(@) cos80^(@)cos160^(@)=-1/8

sin36^(@)+cos36^(@)=sqrt(2)cos9^(@)

Prove that: 4cos12^(0)cos48^(0)cos72^(0)=cos36^(@)

What is the value of (5 sin 75^@ sin 77^@ + 2 cos 13^@ cos 15^@)/(cos 15^@ sin 77^@) - (7 sin 81^@)/(cos 9^@) ?

MARVEL PUBLICATION-TRIGONOMETRIC FUNCTIONS OF COMPOUND ANGLES AND FACTORIZATION FORMULAE-MCQs
  1. Show that : cos9^@.cos18^@.cos36^@.cos72^@=(sin36^@)/(16cos81^@)

    Text Solution

    |

  2. sin10 5^(@)+cos10 5^(@)=

    Text Solution

    |

  3. sin((pi)/(3)+A).cos((pi)/(3)+B)-cos((pi)/(3)+A).sin((pi)/(3)+B)=...

    Text Solution

    |

  4. If 0 ltA lt(pi//2)and0 ltB lt(pi//2), then angle (A-B) lies in…….. Qua...

    Text Solution

    |

  5. If 0 ltA lt(pi//2)and0 ltB lt(pi//2), then angle (A-B) lies in…….. Qua...

    Text Solution

    |

  6. If sinA=3//5 andcosB=9//41, where A,B are both in the first quadrant, ...

    Text Solution

    |

  7. If sinalpha=15//17, (pi//2) ltalpha ltpi and secbeta=13//12, (3pi//2)...

    Text Solution

    |

  8. If tanalpha=3//4 ,alpha in third quadrant, and cosbeta=9//41,beta, in ...

    Text Solution

    |

  9. If sintheta=1//2,cosphi=12//13, where theta lies in the second quadran...

    Text Solution

    |

  10. For any angles A and B, sin(A+B). sin(A-B)=......

    Text Solution

    |

  11. For any angles A and B, cos(A+B).cos(A-B)=…..

    Text Solution

    |

  12. 1+tanA.tan(A//2)=…..

    Text Solution

    |

  13. ( tan3A + tanA)/(tan3A -tan A)=..

    Text Solution

    |

  14. For any angles A,B,C. (sin(A-B))/(cosA.cosB)+(sin(B-C))/(cosB.cosC)+(s...

    Text Solution

    |

  15. sinx+cosx=sqrt2.sin(....)

    Text Solution

    |

  16. cosx-sinx=sqrt2.cos(....)

    Text Solution

    |

  17. tan20^@+tan25^@+tan20^@.tan25^@=....

    Text Solution

    |

  18. tan4 0^@+2tan1 0^@ is equal to

    Text Solution

    |

  19. If A+B=45^@ then (1+tanA)(1+tanB)=

    Text Solution

    |

  20. If 2sin(x+60^@)=cos(x-30^@), then : tan=…..

    Text Solution

    |

  21. tan(45^(@)+A)tan(45^(@)-A)=

    Text Solution

    |