Home
Class 11
MATHS
In DeltaABC, 1/a,1/b,1/c are in A.P. pro...

In `DeltaABC`, `1/a,1/b,1/c` are in A.P. prove that `"cosec"^(2)A/2, "cosec"^(2)B/2, "cosec"C/2` are also in A.P.

Promotional Banner

Topper's Solved these Questions

  • TRIGNOMETRIC FUNCTIONS

    NAGEEN PRAKASHAN|Exercise EXERCISES 3O|12 Videos

  • TRIGNOMETRIC FUNCTIONS

    NAGEEN PRAKASHAN|Exercise EXERCISES 3P|32 Videos

  • TRIGNOMETRIC FUNCTIONS

    NAGEEN PRAKASHAN|Exercise EXERCISES 3M|8 Videos

  • STRAIGHT LINES

    NAGEEN PRAKASHAN|Exercise Exercise|206 Videos

Similar Questions

Explore conceptually related problems

Prove that : (sec^(2)A-1)("cosec"^(2)A-1)=1

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

If a,b,c are in A.P., prove that a^(2)+c^(2)-2bc=2a(b-c) .

if (1)/(b+c),(1)/(c+a),(1)/(a+b) are in A.P. prove that a^(2),b^(2),c^(2) are also in A.P.

If a, b, c are in A.P., prove that a^(2)(b+c),b^(2)(c+a),c^(2)(a+b)" are also in A.P."

If a,b and c be in A.P. prove that cos A cot((A)/(2)),cos B cot((B)/(2)), and cos C cot((C)/(2)) are in A.P.

In DeltaABC , a^(2),b^(2),c^(2) are in A.P. Prove that cotA, cotB, cotC are also in A.P.

If ab+bc+ca!=0 and a,b,c are in A.P. prove that a^(2)(b+c),b^(2)(c+a),c^(2)(a+b) are also in A.P.

"If " a^(2), b^(2), c^(2)" are in A.P., prove that "(1)/(b+c),(1)/(c+a),(1)/(a+b) " are also in A.P."

If a,b,c are in G.P. then prove that (1)/(a+b),(1)/(2b),(1)/(b+c) are also in A.P.

NAGEEN PRAKASHAN-TRIGNOMETRIC FUNCTIONS-EXERCISES 3N
  1. In DeltaABC, if b=7, c=24, a=25, find angleA.

    Text Solution

    |

  2. In DeltaABC, a:b:c=15:7:13, find cosA.

    Text Solution

    |

  3. A triangle side are few 7 cm, 4sqrt3 cm and sqrt(13) cm then the smal...

    Text Solution

    |

  4. In DeltaABC, a=x^(2)-1, b=2x+1, angleC=120^(@), find c.

    Text Solution

    |

  5. In DeltaABC, prove that: a(cosB+cosC)=2(b+c)sin^(2)A/2.

    Text Solution

    |

  6. In DeltaABC, prove that: b(cosA-cosC)=2(c-a)cos^(2)B/2

    Text Solution

    |

  7. In DeltaABC, prove that: a/(b+c)=(1-tanB/2tanC/2)/(1+tanB/2tanC/2)

    Text Solution

    |

  8. In DeltaABC, prove that: a^(2)sin2B+b^(2)sin2A=2absinC

    Text Solution

    |

  9. If any triangle A B C , that: (asin(B-C))/(b^2-c^2)=(bsin(C-A))/(c^2-...

    Text Solution

    |

  10. In DeltaABC, prove that: c(acosB-b cosA)=a^(2)-b^(2)

    Text Solution

    |

  11. In DeltaABC, prove that: (a^(2)sin(B-C))/(sinA) + (b^(2)sin(C-A))/(s...

    Text Solution

    |

  12. In DeltaABC, cosC=(sinA)/(2sinB), prove that b=c.

    Text Solution

    |

  13. In triangleABC, cosA=sinB-cosC,prove that DeltaABC, is right angled.

    Text Solution

    |

  14. In DeltaABC, (sinA)(sinC) = (sin(A-B))/(sin(B-C)), prove that a^(2),b^...

    Text Solution

    |

  15. In a triangle ABC, prove that for any angle theta, b cos (A - theta) +...

    Text Solution

    |

  16. In DeltaABC, 1/a,1/b,1/c are in A.P. prove that "cosec"^(2)A/2, "cosec...

    Text Solution

    |

  17. If a=5, b=12 and c=13, find tanA.

    Text Solution

    |

  18. The sides of a triangle are x^2+x+1, 2x+1 and x^2-1. Prove that the gr...

    Text Solution

    |

  19. i) In DeltaABC, if b=17, c=11 and angleA=60^(@), find tan(B-C)/(2) i...

    Text Solution

    |

  20. In DeltaABC, prove that: (b^(2)-c^(2)+a^(2))tanC=(b^(2)+c^(2)-a^(2))...

    Text Solution

    |