Home
Class 11
MATHS
In triangle A B C , if cosA+cosB+cosC=7/...

In triangle `A B C ,` if `cosA+cosB+cosC=7/4, t h e n R/r` is equal to `3/4` (b) `4/3` (c) `2/3` (d) `3/2`

Promotional Banner

Topper's Solved these Questions

  • STRAIGHT LINES

    CENGAGE PUBLICATION|Exercise All Questions|486 Videos

Similar Questions

Explore conceptually related problems

In triangle A B C , if sinAcosB=1/4 and 3t a n A=t a n B ,t h e ncot^2A is equal to (a)2 (b) 3 (c) 4 (d) 5.

If in triangle ABC cosA+cosB+cosC=3/2 then prove that triangle is equilateral

If in a DeltaABC , cosA+2cosB+cosC=2, then a,b,c are in

In triangle A B C , if r_1=2r_2=3r_3, then a : b is equal to 5/4 (b) 4/5 (c) 7/4 (d) 4/7

In triangle ABC, if r_(1) = 2r_(2) = 3r_(3) , then b : c is equal to

In A B C , prove that cosA+cosB+cosClt=3/2dot

In any triangle ABC, if cosA + cos B + cosC =3/2 , then show that the triangle is equilateral.

If in a triangle ABC, B = (2pi)/3, then cosA +cosC lies in

Let D be the middle point of the side B C of a triangle A B Cdot If the triangle A D C is equilateral, then a^2: b^2: c^2 is equal to 1:4:3 (b) 4:1:3 (c) 4:3:1 (d) 3:4:1

In triangle A B C ,ifPdotQ ,R divides sides B C ,A C , and A B , respectively, in the ratio k :1(inor d e r)dot If the ratio ((a r E A P Q R)/(a r e a A B C)) IS 1/3,t h e nk is equal to 1/3 (b) 2 (c) 3 (d) none of these

CENGAGE PUBLICATION-TRIGONOMETRIC FUNCTIONS-All Questions
  1. Solve : 5cos2theta+2cos^2(theta/2)+1=0,-pi lt theta lt pi

    Text Solution

    |

  2. If x^2+y^2=x^2y^2 then find the range of (5x+12 y+7x y)/(x y) .

    Text Solution

    |

  3. In triangle A B C , if cosA+cosB+cosC=7/4, t h e n R/r is equal to 3/4...

    Text Solution

    |

  4. If 3tanA+4=0, then the value of 2cotA-5cosA+sinA is equal to

    Text Solution

    |

  5. Solve sin2theta+costheta=0

    Text Solution

    |

  6. Two medians drawn from the acute angles of a right angled triangle int...

    Text Solution

    |

  7. For all, x ,y in Rdot find the range of ((x+y)(1-x y))/((1+x^2)(1+y^2...

    Text Solution

    |

  8. A circle centred at 'O' has radius 1 and contains the point A. Segment...

    Text Solution

    |

  9. Solve that equation : costheta+cos3theta-2cos2theta=0

    Text Solution

    |

  10. If x^2+y^2=4 then find the maximum value of (x^3+y^3)/(x+y)

    Text Solution

    |

  11. If inside a big circle exactly n(nlt=3) small circles, each of radius ...

    Text Solution

    |

  12. If b >1,sint >0,cost >0a n d(log)b(sint)=x ,t h e n(log)b(cost) is equ...

    Text Solution

    |

  13. Find the general values of x and y satisfying the equations 5sinx cosy...

    Text Solution

    |

  14. If (x^2)/4+(y^2)/9=1, then find the range of 2x+ydot

    Text Solution

    |

  15. If A is the area and 2s is the sum of the sides of a triangle, then Al...

    Text Solution

    |

  16. Find the general solution of : sqrt(3)sec2theta=2

    Text Solution

    |

  17. Find the value of 2cos^3(pi/7)-cos^2(pi/7)-cos(pi/7)

    Text Solution

    |

  18. In acute angled triangle A B C ,A D is the altitude. Circle drawn with...

    Text Solution

    |

  19. Show that sin^2 5^0+sin^2 10^0+sin^2 15^0+....+sin^2 90^0=9 1/2dot

    Text Solution

    |

  20. Solve (sin^3x/2-cos^3x/2)/(2+sinx)=(cosx)/3

    Text Solution

    |