Home
Class 12
MATHS
If the sum of n terms of an A.P is 2n + ...

If the sum of n terms of an A.P is `2n + 3n^2` , find the `r^(th)` term

A

`2r+3r^(2)`

B

`3r^(2)-4r+1

C

`6r-1`

D

`4r+1`

Text Solution

Verified by Experts

The correct Answer is:
C
Let `S_(n)=2n+2n^(2)`
Now, `S_(n-1)=2(n-1)+3(n-1)^(2)`
`=20-2+3n^(2)+3-6n`
`=3n^(2)-4n+1`
`thereforeT_(n)=S_(n)-S_(n-1)`
`=2n +2n^(2)-(3n^(2)-4n+1)`
`=6n-1`
`T_(r)=6r-1`
Promotional Banner

Topper's Solved these Questions

  • PRACTICE SET 17

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise MATHEMATICS|50 Videos

  • PRACTICE SET 19

    MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS|Exercise Paper 2 (Mathematics)|50 Videos

Similar Questions

Explore conceptually related problems

If sum of n terms of an A.P. is 4n^(2) +7n , find the 15^(th) term.

If sum of n terms of an A.P. is n^(2)+13 , find its 13^(th) term.

If the sum of n terms of an AP is n^2-2n then find its n^(th) term

If the sum of n terms of an A.P is (4n^(2)-3n)/(4) then ,n^(th) term of the A.P

If the sum of terms of an AP is 2n^(2)+5n, then the n^(th) term will be

The sum of n terms of an A.P. is n^(2) + 3n . Find its 20th term.

The sum of first n terms of an AP is (3n^2+6n) Find the n^(th) term and 15^(th) terms of the AP

The sum of n terms of an AP is 3n^2+5n ,then find its 16th term.

If sum of n terms of an AP is 3n^2+n . Find its 10^(th) term.

MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS-PRACTICE SET 18-PAPER 2 (MATHEMATICS)
  1. lim(x to oo) (1-(4)/(x-1))^(3x-1) is equal to

    Text Solution

    |

  2. The middle point of chord x+3y=2 of the conic x^(2)+xy-y^(2)=1, is

    Text Solution

    |

  3. If the sum of n terms of an A.P is 2n + 3n^2 , find the r^(th) term

    Text Solution

    |

  4. Find the value of (320(32)^(1//6)(32)^(1//36)oodot

    Text Solution

    |

  5. Let S={1,,2,34} . The total number of unordered pairs of disjoint s...

    Text Solution

    |

  6. If n(A)=4" and "n(B)=6. Then, the number of one-one function from A to...

    Text Solution

    |

  7. Let f(x) = (x^2 - 1)^(n+1) + (x^2 + x + 1). Then f(x) has local extrem...

    Text Solution

    |

  8. Find the differential equation of all parabolas whose axes are paralle...

    Text Solution

    |

  9. If int1/(xsqrt(1-x^3))dx=alog|(sqrt(1-x^3)-1)/(sqrt(1-x^3)+1)|+b ,t h...

    Text Solution

    |

  10. If p to (qvvr) is false, then the truth values of p,q, and r are, res...

    Text Solution

    |

  11. Which of the following is not a proposition ?

    Text Solution

    |

  12. The maximum value of Z = 4x + 2y subject to the constraints 2x+3y le ...

    Text Solution

    |

  13. If |a|lt1|b|lt1and|x|lt1 then the solution of sin^(-1)((2a)/(1+a^(2)))...

    Text Solution

    |

  14. In a Delta ABC " if " |(1,a,b),(1,c,a),(1,b,c)| =0, then sin^(2) A + s...

    Text Solution

    |

  15. The probability that in the toss of two dice, we obtain the sum 7 or 1...

    Text Solution

    |

  16. int(x^(e-1)+e^(x-1))/(x^(e)+e^(x)) dx is equal to

    Text Solution

    |

  17. The area of the quadrilateral formed by the tangents at the end points...

    Text Solution

    |

  18. lim(n to oo) ((1)/(n)+(1)/(n+1)+...+(1)/(3n)) is equal to

    Text Solution

    |

  19. lim(x to 0)((x)/(sqrt(1+x)-sqrt(1-x))) is equal to

    Text Solution

    |

  20. The equations 2x-3y+6z=4, 5x+7y-14z=1 3x+2y-4z=0, have

    Text Solution

    |