Home
Class 12
MATHS
If A+B+C=pi and cosA=cosB.cosC show that...

If `A+B+C=pi` and cosA=cosB.cosC show that `tanB+tanC=tanA`

Promotional Banner

Topper's Solved these Questions

  • THREE DIMENSIONAL GEOMETRY

    MBD PUBLICATION|Exercise QUESTION BANK|523 Videos

  • VECTORS

    MBD PUBLICATION|Exercise QUESTION BANK|138 Videos

Similar Questions

Explore conceptually related problems

If A+B+C=pi and cosA=cosB.cosC show that 2cotB.cotC=1

If sinA+sinB=a and cosA+cosB=b, show that tan(A+B) = (2ab)/(b^2-a^2)

If sinA+sinB=a and cosA+cosB=b, show that sin(A+B) = (2ab)/(b^2+a^2)

If A+C=B show that tanA.tanB.tanC=tanB-tanA-tanC

If sinA+sinB=a and cosA+cosB=b, show that cos(A+B) = (b^2-a^2)/(b^2+a^2)

If tanA+tanB=a and cotA+cotB=b then show that cot(A+B)=1/a-1/b

Fill int the blanks choosing correct answer from the bracket. In triangle ABC if cosA/a = cosB/b = cosC/c then the triangle is _____.

If tanA=13/27 , tanB=7/20 and A,B are acute, show that A+B = 45^@

If (cosA + 2cosC) : (cosA + 2cosB) = sinB : sinC prove that the triangle either isosceles or right angled.

If a, b and c are vectors such that a .b=a .c, axx b=a xx c, a ne 0 , then show that b=c

MBD PUBLICATION-TRIGONOMETRIC FUNCTIONS-QUESTION BANK
  1. In triangle ABC, prove that tan(B+C)/2=cot(A/2)

    Text Solution

    |

  2. In triangle ABC , prove that cos(A+B)+sinC=sin(A+B)-cosC

    Text Solution

    |

  3. If A+B+C=pi and cosA=cosB.cosC show that tanB+tanC=tanA

    Text Solution

    |

  4. If A+B+C=pi and cosA=cosB.cosC show that 2cotB.cotC=1

    Text Solution

    |

  5. Prove the following : cos(A-D)sin(B-C)+cos(B-D)sin(C-A)+cos(C-D)sin(A-...

    Text Solution

    |

  6. Prove the following : sin2A+sin2B+sin2(A-B) = 4sinA.cosB.cos(A-B)

    Text Solution

    |

  7. Prove the following : cos2A+cos2B+cos2(A-B)+1 = 4cosA.cosB.cos(A-B)

    Text Solution

    |

  8. Prove the following : sin2A+sin2B+sin2C-sin2(A+B+C) 4sin(B+C)sin(C+A...

    Text Solution

    |

  9. Prove the following : sinA+sin3A+sin5A =sin3A(1+2cos2A)

    Text Solution

    |

  10. Prove the following : sinA-sin3A+sin5A = sin3A(2cos2A-1)

    Text Solution

    |

  11. Prove the following : cos(A+B)+sin(A-B) 2sin(45^@+A)cos(45^@+B)

    Text Solution

    |

  12. Prove the following : cos4A-cos4B = 8(cosA-cosB)(cosA+cosB)(cosA-sin...

    Text Solution

    |

  13. Prove the following : (1-tan^2(45^@-A))/(1+tan^2(45^@-A)) = sin2A

    Text Solution

    |

  14. Prove the following : (cosA+sinA)/(cosA-sinA)-(cosA-sinA)/(cosA+sinA) ...

    Text Solution

    |

  15. Prove the following : (1-cos2A+sin2A)/(1+cos2A+sin2A) = tanA

    Text Solution

    |

  16. Prove the following : (sin(A+B)+cos(A-B))/(sin(A-B)+cos(A+B)) = sec2...

    Text Solution

    |

  17. Prove the following : (cos7alpha+cos3alpha-cos5alpha-cosalpha)/(sin7al...

    Text Solution

    |

  18. Prove the following : (sintheta+sin3theta+sin5theta+sin7theta)/(costhe...

    Text Solution

    |

  19. Prove the following : Express 4cosA.cosB.cosC as the sum of four cosin...

    Text Solution

    |

  20. Express cos2A+cos2B+cos2C+cos2(A+B+C) as the product of three cosines.

    Text Solution

    |