Home
Class 11
MATHS
Find a G.P. for which sum of the first ...

Find a G.P. for which sum of the first two terms is -4 and the fifth term is 4 times the third term.

Text Solution

Verified by Experts

The correct Answer is:
N/a

Let first term be 'a' and common ratio be 'r' of G.P.
`Now T_(5)=4*T_(3)implies ar^(4)=4*ar^(2)`
`implies r^(2)=4 implies r= pm2`
`and T_(1)+T_(2)=-4 impliesa+ar=-4`
`implies a=(-4)/(1+r)`
If r=2, the `a=(-4)/(1+2)=(-4)/(3)`
and G.P. `=(-4)/(3),(-8)/(3),(-16)/(3),....`
If r=-2, then `a=(-4)/(1-2)=4`
and G.P. =4,-8,16,....
Promotional Banner

Topper's Solved these Questions

  • SEQUENCE AND SERIES

    NAGEEN PRAKASHAN|Exercise Exercise 9.4|10 Videos
  • SEQUENCE AND SERIES

    NAGEEN PRAKASHAN|Exercise Miscellaneous Exercise|32 Videos
  • SEQUENCE AND SERIES

    NAGEEN PRAKASHAN|Exercise Exercise 9.2|18 Videos
  • RELATIONS AND FUNCTIONS

    NAGEEN PRAKASHAN|Exercise MISCELLANEOUS EXERCISE|12 Videos
  • SETS

    NAGEEN PRAKASHAN|Exercise MISC Exercise|16 Videos

Similar Questions

Explore conceptually related problems

Find a G.P.for which sum of the first two terms is and the fifth term is 4 xx the third term.

In a GP, the sum of first two terms is -4 and the 5th term is 4 times the 3rd term. Find the GP.

Find the G.P. if the sum of its first two terms is 5 and each term is equal to 3 times the sum of its succeeding terms.

In a G.P.the product of the first four terms is 4 and the second term is the reciprocal of the fourth term.The sum of infinite terms of the G.P is

Six numbers are in AP such that their sum is 3 . The first term is 4 times the third term . Then , the fifth term is

The sum of all terms of an arithmetic progression having ten terms except for the first term is 99. Find the third term of the progression if the sum of the first term and the fifth term is equal to 10 .

Find the sum of an infinite G.P. whose first term is 28 and the second term is 4.

The product of three consecutive terms of a GP Is -64 and the first term is four times the third. Find the terms.

In an A.P. the third term is four times the first term, and the sixth term is 17 , find the series.

NAGEEN PRAKASHAN-SEQUENCE AND SERIES-Exercise 9.3
  1. How many terms of G.P. 3,3^(2),3^(3),…… are needed to give the sum 120...

    Text Solution

    |

  2. The sum of first three terms of a G.P is 16 and the sum of the next th...

    Text Solution

    |

  3. Given a G.P with a=729 and 7th term 64,determine S(7).

    Text Solution

    |

  4. Find a G.P. for which sum of the first two terms is -4 and the fifth ...

    Text Solution

    |

  5. If the 4th, 10th and 16 th terms of a G.P. are x, y and z, respectivel...

    Text Solution

    |

  6. Find the sum to n terms of the sequence 8,88,888,8888,……

    Text Solution

    |

  7. Find the sum of the product of the corresponding terms of the sequence...

    Text Solution

    |

  8. Show that the products of the corresponding terms of the sequence a,...

    Text Solution

    |

  9. Find four numbers forming a geometric progression in which the third t...

    Text Solution

    |

  10. If the pth, qth and rth terms of a G.P. are a,b and c, respectively. ...

    Text Solution

    |

  11. If the first and the nth term of a G.P. are a and b, respectively, and...

    Text Solution

    |

  12. Show that the ratio of the sum of first n terms of a G.P. to the sum o...

    Text Solution

    |

  13. If a, b, c and d are in G.P. show that (a^2+b^2+c^2)(b^2+c^2+d^2)=(a b...

    Text Solution

    |

  14. Insert two number between 3 and 81 so that the resulting sequence i...

    Text Solution

    |

  15. Find the value of n so that (a^(n+1)+b^(n+1))/(a^n+b^n)may be the geo...

    Text Solution

    |

  16. The sum of two numbers is 6 times their geometric means, show that nu...

    Text Solution

    |

  17. If A and G be A.M. and GM., respectively between two positive numbers...

    Text Solution

    |

  18. The number of bacteria in a certain culture doubles every hour. If ...

    Text Solution

    |

  19. What will Rs 500 amounts to in 10 years after its deposit in a bank...

    Text Solution

    |

  20. If A.M. and GM. of roots of a quadratic equation are 8 and 5, respe...

    Text Solution

    |