Home
Class 12
MATHS
In DeltaABC, prove that cosA=(b^2+c^2-a^...

In `DeltaABC,` prove that `cosA=(b^2+c^2-a^2)/(2b c)` by vector method.

Promotional Banner

Topper's Solved these Questions

  • PRODUCT OF VECTORS

    ARIHANT MATHS|Exercise JEE Type Solved Examples: Passage Based Type Questions|3 Videos

  • PRODUCT OF VECTORS

    ARIHANT MATHS|Exercise JEE Type Solved Examples: Match Type Questions|4 Videos

  • PROBABILITY

    ARIHANT MATHS|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|55 Videos

  • PROPERTIES AND SOLUTION OF TRIANGLES

    ARIHANT MATHS|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|21 Videos

Similar Questions

Explore conceptually related problems

In any DeltaABC prove by vectors that b^2=c^2+a^2-2 ca cos B.

With the help of vector method, prove that, cosA=(b^2+c^2-a^2)/(2bc)

In any DeltaABC prove by vectors that a^2=b^2+c^2-2 bc cos A.

In any triangle ABC, prove that : (tanC)/(tanA)= (b^2+c^2-a^2)/(a^2+b^2-c^2) .

In a DeltaABC, prove that: 2r le (a cot A+ b cot B+ c cot C)/(3)leR

In DeltaABC , prove that "cosec"(A)/(2)+"cosec"(B)/(2)+"cosec"(C)/(2) ge 6 .

In any triangle ABC, prove that : (cosA)/a+ (cosB)/b+(cosC)/c= (a^2+b^2+c^2)/(2abc) .

In any triangle ABC, prove that : (c^2-a^2+b^2) tan A= (a^2-b^2+ c^2) tan B= (b^2-c^2+a^2) tan C .

In any triangle ABC, prove that : (b^2-c^2) cot A + (c^2-a^2)cot B +(a^2-b^2)cotC=0 .

In DeltaABC ,prove that: a) sin2A + sin2B-sin2C=4cosA cosB sinC

ARIHANT MATHS-PRODUCT OF VECTORS-Exercise (Questions Asked In Previous 13 Years Exam)
  1. In DeltaABC, prove that cosA=(b^2+c^2-a^2)/(2b c) by vector method.

    Text Solution

    |

  2. Let O be the origin and let PQR be an arbitrary triangle. The point S ...

    Text Solution

    |

  3. Let O be the origin and vec(OX) , vec(OY) , vec(OZ) be three unit vec...

    Text Solution

    |

  4. Let O be the origin, and O X , O Y , O Z be three unit vectors ...

    Text Solution

    |

  5. Let a, b and c be three unit vectors such that atimes(btimesc)=(sqrt(3...

    Text Solution

    |

  6. Let vec a , vec b and vec c be three non-zero vectors such that no ...

    Text Solution

    |

  7. If vec a , vec ba n d vec c are unit vectors satisfying | vec a- v...

    Text Solution

    |

  8. The vector(s) which is/are coplanar with vectors hat i+ hat j+2 hat...

    Text Solution

    |

  9. Let vec a= hat i+ hat j+ hat k , vec b= hat i- hat j+ hat ka n d vec ...

    Text Solution

    |

  10. Two adjacent sides of a parallelogram A B C D are given by vec A B=...

    Text Solution

    |

  11. Let P,Q R and S be the points on the plane with position vectors -2hat...

    Text Solution

    |

  12. If aa n db are vectors in space given by vec a=( hat i-2 hat j)/(sq...

    Text Solution

    |

  13. If veca,vecb,vecc and vecd are unit vectors such that (vecaxxvecb)*(...

    Text Solution

    |

  14. The edges of a parallelopiped are of unit length and are parallel to ...

    Text Solution

    |

  15. Let two non-collinear unit vectors veca and vecb form an acute angle. ...

    Text Solution

    |

  16. Let the vectors PQ,OR,RS,ST,TU and UP represent the sides of a regular...

    Text Solution

    |

  17. The number of distinct real values of lambda , for which the vectors...

    Text Solution

    |

  18. If veca, vecb, vecc are unit vectors such that veca+vecb+vecc=0, find...

    Text Solution

    |

  19. Let A be vector parallel to line of intersection of planes P1 and P2. ...

    Text Solution

    |

  20. Let vec a= hat i+2 hat j+ hat k , vec b= hat i- hat j+ hat ka n d vec...

    Text Solution

    |

  21. Find the 7th term of GP if the first term is 7 and common ratio is 2.

    Text Solution

    |