Home
Class 14
MATHS
If sin 18^@=(sqrt(5)-1)/4 then what is t...

If `sin 18^@=(sqrt(5)-1)/4` then what is the value of `sin 81^@`

A

`(sqrt(3+sqrt5)+sqrt(5-sqrt5))/(4)`

B

`(sqrt(3+sqrt5)+sqrt(5+sqrt5))/(4)`

C

`(sqrt(3-sqrt5)+sqrt(5-sqrt5))/(4)`

D

`(sqrt(3+sqrt5)-sqrt(5-sqrt5))/(4)`

Text Solution

Verified by Experts

The correct Answer is:
A
Promotional Banner

Topper's Solved these Questions

  • TRIGONOMETRY

    PUNEET DOGRA|Exercise PREV YEAR QUESTIONS|163 Videos

  • STATISTICS

    PUNEET DOGRA|Exercise PRE YEAR QUESTIONS |163 Videos

  • VECTOR

    PUNEET DOGRA|Exercise Prev Year Questions|134 Videos

Similar Questions

Explore conceptually related problems

If sin18^(@)=(sqrt(5)-1)/(4) then what is the value of sin81^(@)

The value of sin 18^@

Find the value of sin18^@

The value of sin 18^(@) is

What is the value of sin 18^@ cos 36^@ ?

The value of sin18^(@) is

If theta=18^(@) , then what is the value of 4sin^(2)theta+2sintheta ?

It is given that sin54^(@)=(sqrt(5)+1)/(4), the value of (64sin^(4)27^(@)-64sin^(2)27^(@)+6)^(2)-15(sin^(2)27^(@)+sin^(2)63^(@)) is equal to

PUNEET DOGRA-TRIGONOMETRY-PREV YEAR QUESTIONS
  1. If x = sin 70^@. Sin50^@ and y=cos60^@ cos80^@, then what is xy equal ...

    Text Solution

    |

  2. (1+cos.(pi)/(8))(1+cos.(3pi)/(8))(1+cos.(5pi)/(8))(1+cos.(7pi)/(8)) is...

    Text Solution

    |

  3. If sin 18^@=(sqrt(5)-1)/4 then what is the value of sin 81^@

    Text Solution

    |

  4. (1-tan2^(@)cot62^(@))/(tan152^(@)-cot88^(@)) =?

    Text Solution

    |

  5. Consider the following statement : 1. If ABC is an equilateral trian...

    Text Solution

    |

  6. If A=(cos150^@) and B=(sin60^@), then what is A/B equal to ?

    Text Solution

    |

  7. Consider a triangle ABC in which cos A + cos B + cos C = sqrt(3) "sin"...

    Text Solution

    |

  8. Consider a DeltaABC in which CosA+CosB+CosC=sqrt(3)Sin""(pi)/(3) Wha...

    Text Solution

    |

  9. If sin x + sin y = a and cos x + cos y = b, than tan^2((x+y)/(2))+tan^...

    Text Solution

    |

  10. In triangle ABC, if cos^(2)A + cos^(2)B - cos^(2) C = 1, then identify...

    Text Solution

    |

  11. Consider a DeltaABC satisfying 2aSin^(2)((C)/(2))+2cSin^(2)((A)/(2))=2...

    Text Solution

    |

  12. If p=tan(-(11pi)/(6)).q=tan((21pi)/(4)) and r=cot((383pi)/(6)), then w...

    Text Solution

    |

  13. The value of sin^2 5^@ + sin^2 10^@ + sin^2 15^@ + sin^2 20^@ + ... + ...

    Text Solution

    |

  14. On simplifying (sin^3A+sin3A)/(sinA)+(cos^3A-cos3A)/(cosA) we get

    Text Solution

    |

  15. Directions (FOR NEXT TWO): Let alpha be the root of the equation 25cos...

    Text Solution

    |

  16. Directions (FOR NEXT TWO): Let alpha be the root of the equation 25cos...

    Text Solution

    |

  17. (1-sinA+cosA)^2 is equal to :

    Text Solution

    |

  18. (tantheta)/(1-cottheta)+(cottheta)/(1-tantheta) is equal to -

    Text Solution

    |

  19. Let theta be a positive angle. Is the number of degrees in is divided ...

    Text Solution

    |

  20. What is (cos7x-cos3x)/(sin7x-2sin5x+sin3x) equal to?

    Text Solution

    |