Home
Class 12
MATHS
If 1/a,1/b,1/c are in A.P and a,b -2c, a...

If `1/a,1/b,1/c` are in A.P and a,b -2c, are in G.P where a,b,c are non-zero then

Text Solution

Verified by Experts

The correct Answer is:
A, B, C, D

we have `b=(2ac)/(a+c)` and `b^(2)=-2ac`
`thereforeb=(-b^(2))/(a+c)`
`rArr a+b+c=0`
`rArr2b-2a-2c`
Therefore, -2a,b,-2c are in A.P.
Also, `a^(3)+b^(3)+c^(3)=3abc`
Since `b^(2)=-2ac,b^(4)=4a^(2)c^(2)`
So, `a^(2),b^(2),4c^(2)` are in G.P.
Since a+b+c=0, equations `ax^(2)+bx+c=0` has one root x=1
So, equation has real roots.
Promotional Banner

Topper's Solved these Questions

  • PROGRESSION AND SERIES

    CENGAGE|Exercise EXERCIESE ( MULTIPLE CORRECT ANSWER TYPE )|2 Videos
  • PROGRESSION AND SERIES

    CENGAGE|Exercise EXERCIESE ( MATRIX MATCH TYPE )|3 Videos
  • PROGRESSION AND SERIES

    CENGAGE|Exercise Exercise (Single)|93 Videos
  • PROBABILITY II

    CENGAGE|Exercise JEE Advanced Previous Year|25 Videos
  • PROPERTIES AND SOLUTIONS OF TRIANGLE

    CENGAGE|Exercise JEE Advanced Previous Year|11 Videos

Similar Questions

Explore conceptually related problems

If a,b, and c are in A.P and b-a,c-b and a are in G.P then a:b:c is

If a+c , a+b , b+c are in G.P and a,c,b are in H.P. where a , b , c gt 0 , then the value of (a+b)/(c ) is

If a , b, c, … are in G.P. then 2a,2b,2c,… are in ….

If a,b, and c are in G.P then a+b,2b and b+ c are in

If a, b, c are in A.P., b, c, d are in G.P. and 1/c,1/d,1/e are in A.P. prove that a,c,e are in GP.

If l n(a+c),l n(a-c)a n dl n(a-2b+c) are in A.P., then (a) a ,b ,c are in A.P. (b) a^2,b^2, c^2, are in A.P. (c) a ,b ,c are in G.P. d. (d) a ,b ,c are in H.P.

If the angles A,B,C of a triangle are in A.P. and sides a,b,c, are in G.P., then prove that a^2, b^2,c^2 are in A.P.

If a,b,c are in H.P , b,c,d are in G.P and c,d,e are in A.P. , then the value of e is

If a ,1/b ,a n d1/p ,q ,1/r from two arithmetic progressions of the common difference, then a ,q ,c are in A.P. if p ,b ,r are in A.P. b. 1/p ,1/b ,1/r are in A.P. c. p ,b ,r are in G.P. d. none of these

If a ,b ,c are in G.P. and a-b ,c-a ,a n db-c are in H.P., then prove that a+4b+c is equal to 0.

CENGAGE-PROGRESSION AND SERIES-Exercise (Multiple & Comprehension)
  1. The numbers 1, 4, 16 can be three terms (not necessarily consecutive) ...

    Text Solution

    |

  2. The sum of an infinite geometric series is 162 and the sum of its firs...

    Text Solution

    |

  3. If 1/a,1/b,1/c are in A.P and a,b -2c, are in G.P where a,b,c are non-...

    Text Solution

    |

  4. Sum of an infinite G.P is 2 and sum of its two terms is 1.If its secon...

    Text Solution

    |

  5. For 0 lt phi lt pi//2 , if x =Sigma(n=0)^(oo) cos^(2n) phi ,y=Sigma(n...

    Text Solution

    |

  6. For the series, S=1+1/((1+3))(1+2)^2+1/((1+3+5))(1+2+3)^2+1/((1+3+5+7)...

    Text Solution

    |

  7. If sum(r=1)^n r(r+1)(2r+3)=a n^4+b n^3+c n^2+d n+e , then a. a-b=d-c ...

    Text Solution

    |

  8. If Sn=1^2-2^2+3^2-4^2+5^2-6^2+...... ,t h e n

    Text Solution

    |

  9. 1/(sqrt(2)+sqrt(5))+1/(sqrt(5)+sqrt(8))+1/(sqrt(8)+sqrt(11))+ n terms ...

    Text Solution

    |

  10. If vec a= hat i+2 hat j+3 hat k and vec b=2 hat i+4 hat j−5 hat k rep...

    Text Solution

    |

  11. Given that x+y+z =15 when a,x,y,z,b are in A.P and 1/x+1/y+1/z=5/3 whe...

    Text Solution

    |

  12. If a, b and c are in H.P., then the value of ((ac+ab-bc)(ab+bc-ac))/(a...

    Text Solution

    |

  13. If p,q and r are in A.P then which of the following is / are true ?

    Text Solution

    |

  14. If x^2+9y^2+25 z^2=x y z((15)/2+5/y+3/z),t h e n x ,y ,a n dz are in ...

    Text Solution

    |

  15. If A1, A2, G1, G2, ; a n dH1, H2 are two arithmetic, geometric and har...

    Text Solution

    |

  16. If 1/(b-a)+1/(b-c)=1/a+1/c , then a ,b ,a n dc are in H.P. a ,b ,a n d...

    Text Solution

    |

  17. If a,b,c are three distinct numbers in G.P., b,c,a are in A.P and a,bc...

    Text Solution

    |

  18. If a,b,c are in A.P and a^2,b^2,c^2 are in H.P then which is of the fo...

    Text Solution

    |

  19. If first and (2n-1)^(th) terms of A.P., G.P. and H.P. are equal and th...

    Text Solution

    |

  20. Let E=1/(1^2)+1/(2^2)+1/(3^2)+ Then, a.E<3 b. E >3//2 c. E >2 d. E<2

    Text Solution

    |