Home
Class 12
MATHS
In a triangle ABC ,a^2 cos^2 A=b^2+c^2, ...

In a triangle `ABC ,a^2 cos^2 A=b^2+c^2`, then

A

`A gt pi/2`

B

`A lt pi/4`

C

`pi/4 lt A lt pi/2`

D

`A=pi/2`

Text Solution

Verified by Experts

The correct Answer is:
A
Promotional Banner

Topper's Solved these Questions

  • PROPERTIES OF TRIANGLES

    ML KHANNA|Exercise Problem Set (2)(TRUE AND FALSE)|2 Videos

  • PROPERTIES OF TRIANGLES

    ML KHANNA|Exercise Problem Set (2)(FILL IN THE BLANKS)|3 Videos

  • PROPERTIES OF TRIANGLES

    ML KHANNA|Exercise Problem Set (1)(FILL IN THE BLANKS)|10 Videos

  • PROGRESSIONS

    ML KHANNA|Exercise MISCELLANEOUS EXERCISE (ASSERTION/REASON) |1 Videos

  • RECTANGULAR CARTESIAN CO-ORDINATE SYSTEM AND THE STRAIGHT LINE

    ML KHANNA|Exercise COMPREHENSION |11 Videos

Similar Questions

Explore conceptually related problems

In triangle ABC,cos A+2cos B+cos C=2, then-

If in a triangle Delta ABC,a^(2)cos^(2)A-b^(2)-c^(2)=0 then

If in a triangle ABC, (bc)/(2 cos A) = b^(2) + c^(2) - 2bc cos A then prove that the triangle must be isosceless

In a triangle ABC,bc cos^(2)(A)/(2)+ca cos^(2)(B)/(2)+ab cos^(2)(C)/(2)=

In triangle ABC, cos^2A + cos^2B - cos^2C = 1, then the triangle is necessarily

In a triangle ABC,cos^(2)A+cos^(2)B+cos^(2)C=

If in a triangle ABC,b cos^(2)((A)/(2))+a cos^(2)((B)/(2))=(3)/(2)c then a,c,b are:

Show that, in a triangle ABC. a^(2) = (b - c)^(2) cos^(2) (A/2) + (b + c)^(2) sin^(2) (A/2) .

ML KHANNA-PROPERTIES OF TRIANGLES -Problem Set (2)(MULTIPLE CHOICE QUESTIONS)
  1. With usual notations, if in a triangle ABC (b+c)/(11) = (c+a)/(12) = ...

    Text Solution

    |

  2. In a triangle ABC, a^4 +b^4 +c^4 = 2(a^2 +c^2)b^2 then the angle B is

    Text Solution

    |

  3. In a triangle ABC ,a^2 cos^2 A=b^2+c^2, then

    Text Solution

    |

  4. If in a triangle sin^4 A+sin^4 B + sin^4 C = sin^2 B sin^2 C+2 sin^2 C...

    Text Solution

    |

  5. If A=60^@, " then " b/(c+a)+c/(a+b) =

    Text Solution

    |

  6. The sides of a triangle are three consecutive natural numbers and its ...

    Text Solution

    |

  7. If D id the mid-point of the side BC of a triangle ABC and AD is perpe...

    Text Solution

    |

  8. Prove that ((a+b+c)(b+c-a)(c+a-b)(a+b-c))/(4b^2c^2)=sin^2A

    Text Solution

    |

  9. Let 'l' is the length of median from the vertex A to the side BC of a ...

    Text Solution

    |

  10. If a triangle ABC, D is the mid point of side BC and angleADB =theta "...

    Text Solution

    |

  11. The straight roads intersect at an angle of 60°. A bus on one road is ...

    Text Solution

    |

  12. If the angles A,B,C of a triangle are in A.P. and sides a,b,c, are in ...

    Text Solution

    |

  13. If the anngle A,B,C of a Delta ABC are in A.P then :-

    Text Solution

    |

  14. If in a triangles a cos^(2)(C/2)+c cos^(2)(A/2)=(3b)/2, then the sides...

    Text Solution

    |

  15. In any DeltaABC, prove that (a-b)^(2)cos^(2)""C/2+(a+b)^(2)sin^(2)""C/...

    Text Solution

    |

  16. If cos A+cos B+2cos C=2 then the sides of the A B C are in A.P. (b) G...

    Text Solution

    |

  17. In a triangle ABC with fixed base BC, the vertex A moves such that cos...

    Text Solution

    |

  18. If in a triangle ABC, 2 (cos A)/(a)+(cos B)/(b)+2(cos C)/c=(a)/(bc)+b/...

    Text Solution

    |

  19. In Delta ABC, (a + b+ c) (b + c -a) = kbc if

    Text Solution

    |

  20. In a triangle ABC, 2ac sin((A-B+C)/2) =

    Text Solution

    |