Home
Class 11
MATHS
In triangleABC, prove that cos(A+B)+cosC...

In `triangleABC`, prove that
cos(A+B)+cosC=0

Promotional Banner

Topper's Solved these Questions

  • TRIGNOMETRIC FUNCTIONS

    JBD PUBLICATION|Exercise EXAMPLE|67 Videos

  • STRAIGHT LINES

    JBD PUBLICATION|Exercise EXAMPLE|39 Videos

Similar Questions

Explore conceptually related problems

In triangleABC , prove that cos((A+B)/(2))=sinC/2

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 : a sin (B -C) + b sin (C -A) +c sin (A-B) = 0 .

If A,B,C are the angles of a triangle then prove that cosA+cosB-cosC=-1+4cos(A/2)cos(B/2)sin(C/2)

If O is a point inside a triangleABC , prove that angleBOC=angleBAC+angleABO+angleACO .

In any triangle A B C , prove the projection formula a=b cosC+c cosB using vector method.

In any quadrilateral ABCD, prove that: sin (A + B) + sin(C +D)=0 .

Use vectors to prove that in triangleABC : b=c cos A+a cos C .

In a triangleABC , prove by vector method that cos2A+cos2B+cos2Cge(-3)/(2) .

In triangleABC , D is the mid point of the side AB and E is centroid of triangleCDA . If OE*CD=0 , where O is the circumcentre of triangleABC , using vectors prove that AB=AC.

JBD PUBLICATION-TRIGNOMETRIC FUNCTIONS-EXAMPLE
  1. An athlete runs 4 times around a circular running a path to describe 1...

    Text Solution

    |

  2. Prove that: cot^2frac (pi)(6)+cosecfrac (5pi)(6)+3tan^2frac (pi)(6)=6

    Text Solution

    |

  3. In triangleABC, prove that cos(A+B)+cosC=0

    Text Solution

    |

  4. In triangleABC, prove that cos((A+B)/(2))=sinC/2

    Text Solution

    |

  5. Prove the following: cos((3pi)/2+x)cos(2pi+x)[cot((3pi)/2-x)+cot(2pi+x...

    Text Solution

    |

  6. If tan alpha= (m)/(m+1) and tan beta=(1)/(2m+1), the find the value o...

    Text Solution

    |

  7. If tan(alpha+theta)=ntan(alpha-theta), show that:(n+1)sin 2theta=(n-1)...

    Text Solution

    |

  8. Prove that:(1+sin2x-cos2x)/(1+sin2x+cos2x)=tanx

    Text Solution

    |

  9. Show that sqrt(2+sqrt(2+sqrt(2+2cos 8)))=2cos theta

    Text Solution

    |

  10. Find sinfrac(x)(2), cosfrac(x)(2) and tanfrac(x)(2) in the following:-...

    Text Solution

    |

  11. Find sinfrac(x)(2), cosfrac(x)(2) and tanfrac(x)(2) in the following:-...

    Text Solution

    |

  12. Prove the following: (cos4x + cos3x + cos2x)/(sin4x + sin 3x + sin 2x)...

    Text Solution

    |

  13. Show that:(sin11x sinx+sin7x sin3x)/(cos11x sinx + cos7x sin3x)=tan8x

    Text Solution

    |

  14. Prove the following: sin2 x + 2 sin 4x + sin 6x = 4 cos^2 x sin 4x

    Text Solution

    |

  15. Find the general solution for each of the following equations: 2cos^2x...

    Text Solution

    |

  16. Find the general solution for each of the following equations: 4 sin^2...

    Text Solution

    |

  17. Find the general solution of the following equations: sec^2 2x = 1- ta...

    Text Solution

    |

  18. Find the general solution of the following trignometric equations: tan...

    Text Solution

    |

  19. Find the general solution of the following trignometric equations: tan...

    Text Solution

    |

  20. Prove that: (cosx-cosy)^2 +(sinx-siny)^2=4 sin^2frac (x-y)(2)

    Text Solution

    |