Home
Class 11
MATHS
Find the rth term of an AP sum of...

Find the rth term of an AP sum of whose first n terms is `2n+3n^(2).`

Text Solution

Verified by Experts

Given that sum of n terms of an AP.
`S_(n)=2n+3n^(2)`
` T_(n)=S_(n)-S_(n-1)`
`=(2n+3n^(2))-[2(n-1)+3(n-1)^(2)]`
`=(2n+3n^(2))-[2n-2+3(n^(2)+1-2n)]`
` =(2n+3n^(2))-(2n-2+3n^(2)+3-6n)`
`=2n+3n^(2)-2n+2-3n^(2)-3+6n`
` =6n-1`
`rth "term " T_(r)=6r-1`
Promotional Banner

Topper's Solved these Questions

  • SEQUENCE AND SERIES

    NCERT EXEMPLAR ENGLISH|Exercise long answer type questions|4 Videos

  • SEQUENCE AND SERIES

    NCERT EXEMPLAR ENGLISH|Exercise Objective type Question|10 Videos

  • RELATIONS AND FUNCTIONS

    NCERT EXEMPLAR ENGLISH|Exercise True /False|5 Videos

  • SETS

    NCERT EXEMPLAR ENGLISH|Exercise TRUE AND FALSE|6 Videos

Similar Questions

Explore conceptually related problems

Find the rth term of an A.P., sum of whose first n terms is 2n + 3n^(2) .

Find the rth term of an A.P., the sum of whose first n terms is 3n^2+4n

Write the n t h term of an A.P. the sum of whose n terms is S_n .

Write the common difference of an A.P. the sum of whose first \ \ n terms is P/2n^2+Q n

Find the common difference of the A. P, the Sum of whose first n terms is 2n + 5n^(2) .

Find the sum of first 25 terms of an A.P. whose nth term is 1- 4n

Find the sum to n terms of an A.P. whose nth terms is t_n=5+6n,n in N.

Find the sum of n terms of an A.P. whose n t h terms is given by a_n=5-6n .

Find the sum of the first 25 terms of an A.P. whose n t h term is given by a_n=2-3n .

Find the sum of 'n' terms of an A.P. whose nth term is 2n+1.