Advertisements
Advertisements
Question
The nth term of an A.P., the sum of whose n terms is Sn, is
Options
Sn + Sn−1
Sn − Sn−1
Sn + Sn+1
Sn − Sn+1
Advertisements
Solution
A.P. we use following formula,
`a_n = S_n - S_(n - 1)`
So, the nth term of the A.P. is given by `a_n = S_n - S_(n - 1)`.
APPEARS IN
RELATED QUESTIONS
Find the sum of first 22 terms of an AP in which d = 7 and 22nd term is 149.
Find the sum of the following arithmetic progressions:
`(x - y)/(x + y),(3x - 2y)/(x + y), (5x - 3y)/(x + y)`, .....to n terms
Find the sum of the first 25 terms of an A.P. whose nth term is given by an = 7 − 3n
Find the sum 25 + 28 + 31 + ….. + 100
Find the middle term of the AP 6, 13, 20, …., 216.
If (2p – 1), 7, 3p are in AP, find the value of p.
In an A.P. the 10th term is 46 sum of the 5th and 7th term is 52. Find the A.P.
If the sum of first p terms of an A.P. is equal to the sum of first q terms then show that the sum of its first (p + q) terms is zero. (p ≠ q)
The 9th term of an A.P. is equal to 6 times its second term. If its 5th term is 22, find the A.P.
The sum of first n terms of an A.P. is 5n − n2. Find the nth term of this A.P.
In a school, students decided to plant trees in and around the school to reduce air pollution. It was decided that the number of trees, that each section of each class will plant, will be double of the class in which they are studying. If there are 1 to 12 classes in the school and each class has two sections, find how many trees were planted by the students.
A piece of equipment cost a certain factory Rs 60,000. If it depreciates in value, 15% the first, 13.5% the next year, 12% the third year, and so on. What will be its value at the end of 10 years, all percentages applying to the original cost?
Write the value of a30 − a10 for the A.P. 4, 9, 14, 19, ....
The 9th term of an A.P. is 449 and 449th term is 9. The term which is equal to zero is
Find the sum of those integers from 1 to 500 which are multiples of 2 or 5.
[Hint (iii) : These numbers will be : multiples of 2 + multiples of 5 – multiples of 2 as well as of 5]
Find the sum:
`(a - b)/(a + b) + (3a - 2b)/(a + b) + (5a - 3b)/(a + b) +` ... to 11 terms
Find the sum of the integers between 100 and 200 that are not divisible by 9.
The ratio of the 11th term to the 18th term of an AP is 2 : 3. Find the ratio of the 5th term to the 21st term, and also the ratio of the sum of the first five terms to the sum of the first 21 terms.
Find the sum of first 16 terms of the A.P. whose nth term is given by an = 5n – 3.
