Home
Class 11
MATHS
Find the value of tan (pi/8)...

Find the value of `tan (pi/8)`

Text Solution

Verified by Experts

Let .(x)=(pi)/(8) .. Then .2 (x)=(pi)/(4).
Now .tan 2 (x)=(2 tan (x))/(1-tan ^(2) (x)).
or .tan (pi)/(4)=(2 tan (pi)/(8))/(1-tan ^(2) (pi)/(8)).
Let .y=tan (pi)/(8).. Then .1=(12 y)/(1-y^(2)).
or . y^(2)+2 y-1=0.
Promotional Banner

Topper's Solved these Questions

  • STRAIGHT LINES

    V PUBLICATION|Exercise QUESTIONBANK|99 Videos

Similar Questions

Explore conceptually related problems

Find the value of tan((19pi)/3)

(ii)Find the value of tan(pi/4+theta)tan(pi/4-theta)

Find tha value of tan 75^@

Find :the value of 'tan(13 pi / 12) '.

Find the value of cot(tan^(-1) a + cot^(-1) a)

Find the value of 4 tan^(-1)""(1)/5 - tan^(-1)""(1)/70+tan^(-1)""1/99

(ii)Find the value of sin(31/3 pi)

Find the value of cot((-15pi)/4)

Find the value of sin((-11pi)/3)

Find the value of int_(0)^(pi//2)sin2xlogtan xdx .

V PUBLICATION-TRIGNOMETRC FUNCTIONS-QUESTION BANK
  1. If sin x=(3)/(5), cos y=-(12)/(13), where 'x' and 'y' both lie in seco...

    Text Solution

    |

  2. Prove that cos 2 x cos (x/2)-cos 3 x cos ((9x)/2)=sin 5 x sin ((5 x)/...

    Text Solution

    |

  3. Find the value of tan (pi/8)

    Text Solution

    |

  4. If tan x^(circ)=(3)/(4), piltxlt(3 pi)/(2), find the value of sin (x)...

    Text Solution

    |

  5. Show that cos ^(2) x+cos ^(2)(x+(pi)/(3))+cos ^(2) (x-(pi)/(3))=(3)/(2...

    Text Solution

    |

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

    Text Solution

    |

  7. Prove that (sin 3 x+sin x) sin x+(cos 3 x-cos x)cosx=0

    Text Solution

    |

  8. Prove that (cosx+cosy)^2+(sinx-siny)^2=4cos^2((x+y)/2)

    Text Solution

    |

  9. Prove that (cos x-cos y)^(2)+(sin x-sin y)^(2)=4 sin ^(2)((x-y)/(2))

    Text Solution

    |

  10. Prove that sin 2 x+2 sin 4 x+sin 6 x=4 cos ^(2) x sin 4 x

    Text Solution

    |

  11. Prove that ((sin 7 x+sin 5 x)+(sin 9 x+sin 3 x))/((cos 7 x+cos 5 x)+(c...

    Text Solution

    |

  12. Show that sin 3 x+sin 2 x-sin x=4 sin x cos (x/2) cos ((3 x)/2)

    Text Solution

    |

  13. Find sin(x/2) , cos(x/2) , and tan(x/2) if tanx=-4/3 and x is in the s...

    Text Solution

    |

  14. Find sin(x/2) , cos(x/2) and tan(x/2) if cosx=(-1/3) and x lies in the...

    Text Solution

    |

  15. Find sin(x/2), cos(x/2) and tan(x/2) if sinx=1/4 and x lies in the sec...

    Text Solution

    |

  16. Prove that (sin x)/(1+cos x)=tan (x/2) Find the domain and range of f(...

    Text Solution

    |

  17. Hence write the value of cos 75^@.

    Text Solution

    |

  18. If (sin (x+y))/(sin (x-y))=(a+b)/(a-b), show that a tan y=b tan x

    Text Solution

    |

  19. Prove that cos 24^(circ)+cos 55^(circ)+cos 125^(circ)+cos 204^(circ)+...

    Text Solution

    |

  20. Prove that sqrt(2+sqrt(2+sqrt(2+2 cos 8 theta)))=2 cos theta

    Text Solution

    |