Home
Class 12
MATHS
In a A B C , if tanA/2,tanB/2,tanC/2a r...

In a ` A B C ,` if `tanA/2,tanB/2,tanC/2a r einAdotPdot,` then show that `cosA ,cosB ,cosC` are in `AdotPdot`

Text Solution

Verified by Experts

The correct Answer is:
`cos B -cos A =cos C-cos B.`
Promotional Banner

Topper's Solved these Questions

  • PROPERTIES AND SOLUTION OF TRIANGLES

    ARIHANT MATHS ENGLISH|Exercise SOLVED EXAMPLES|1 Videos

  • PROPERTIES AND SOLUTION OF TRIANGLES

    ARIHANT MATHS ENGLISH|Exercise Exercise For Sesssion 1|20 Videos

  • PRODUCT OF VECTORS

    ARIHANT MATHS ENGLISH|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|51 Videos

  • SEQUENCES AND SERIES

    ARIHANT MATHS ENGLISH|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|38 Videos

Similar Questions

Explore conceptually related problems

In a /_\A B C , if tanA/2,tanB/2,tanC/2"are in"AdotPdot, then show that cosA ,cosB ,cosC are in AdotPdot

Prove that cosA+cosB+cosC=1+r/R

Prove that cosA+cosB+cosC=1+r/R

(a+b+c)(cosA+cosB+cosC)

In a DeltaABC , if tanA/2=5/6 and tanB/2=20/37 then tanC/2=

If a^2, b^2,c^2 are in A.P., then prove that tanA ,tanB ,tanC are in H.P.

If In (a+c),ln(a-c),ln(a-2b+c) are in AdotPdot, then a , b , c ,a r einAdotPdot (b) a^2,b^2,c^2a r einAdotPdot a , b , c are in GdotPdot (d) a , b , c are in HdotPdot

Prove that : (a b c)/scosA/2cosB/2cosC/2=

In triangle A B C ,tanA+tanB+tanC=6a n dtanAtanB=2, then the values of tanA ,tanB ,tanC are, respectively (a) 1,2,3 (b) 3,2//3,7//3 (c) 4,1//2 ,3//2 (d) none of these

In DeltaABC , prove that: tanA/2tanB/2+tanB/2tanC/2+tanC/2tanA/2=1

ARIHANT MATHS ENGLISH-PROPERTIES AND SOLUTION OF TRIANGLES -Exercise (Questions Asked In Previous 13 Years Exam)
  1. In a A B C , if tanA/2,tanB/2,tanC/2a r einAdotPdot, then show that c...

    Text Solution

    |

  2. In a triangle XYZ, let x, y, z be the lengths of sides opposite to the...

    Text Solution

    |

  3. In a triangle the sum of two sides is x and the product of the same is...

    Text Solution

    |

  4. Consider a triangle A B C and let a , ba n dc denote the lengths of th...

    Text Solution

    |

  5. about to only mathematics

    Text Solution

    |

  6. Let PQR be a triangle of area Delta with a = 2, b = 7//2, and c = 5//2...

    Text Solution

    |

  7. If the angle A ,Ba n dC of a triangle are in an arithmetic propression...

    Text Solution

    |

  8. Let A B C be a triangle such that /A C B=pi/6 and let a , b and c deno...

    Text Solution

    |

  9. A triangle A B C with fixed base B C , the vertex A moves such that co...

    Text Solution

    |

  10. Let A B Ca n dA B C ' be two non-congruent triangles with sides A B=4,...

    Text Solution

    |

  11. A straight line through the vertex P of a triangle P Q R intersects th...

    Text Solution

    |

  12. Consider the circle x^2 + y^2 = 9 and the parabola y^2 = 8x. They inte...

    Text Solution

    |

  13. Consider the circle x^2 + y^2 = 9 and the parabola y^2 = 8x. They inte...

    Text Solution

    |

  14. Consider the circle x^2 + y^2 = 9 and the parabola y^2 = 8x. They inte...

    Text Solution

    |

  15. Internal bisector of /A of triangle ABC meets side BC at D. A line dra...

    Text Solution

    |

  16. One angle of an isosceles triangle is 120^0 and the radius of its incr...

    Text Solution

    |

  17. In Delta ABC, which one is true among the following ?

    Text Solution

    |

  18. Let a vertical tower A B have its end A on the level ground. Let C be ...

    Text Solution

    |

  19. ABCD is a trapezium such that AB and CD are parallel and BC bot CD. If...

    Text Solution

    |

  20. For a regular polygon, let r and R be the radii of the inscribed and t...

    Text Solution

    |

  21. In triangle A B C , let /c=pi/2dot If r is the inradius and R is circu...

    Text Solution

    |