Advertisements
Advertisements
प्रश्न
Find the sum of the first 11 terms of the A.P : 2, 6, 10, 14, ...
उत्तर
In the given problem, we need to find the sum of terms for different arithmetic progressions. So, here we use the following formula for the sum of n terms of an A.P.,
`S_n = n/2[2a + (n - 1)d]`
Where; a = first term for the given A.P.
d = common difference of the given A.P.
n = number of terms
2, 6, 10, 14, ... to 11 terms
Common difference of the A.P. (d) = `a_2 - a_1`
= 6 - 2
= 4
Number of terms (n) = 11
The first term for the given A.P. (a) = 2
So, using the formula we get,
`S_n = 11/2 [2(2) + (11 - 1)(4)]`
`= (11/2)[4 + (10)(4)]`
`= (11/2)[4 + 40]`
`= (11/2) [44]`
= 242
Therefore, the sum of first 11 terms for the given A.P. is 242
APPEARS IN
संबंधित प्रश्न
Find how many integers between 200 and 500 are divisible by 8.
Find the sum of the following arithmetic progressions
`(x - y)^2,(x^2 + y^2), (x + y)^2,.... to n term`
Find the sum of all integers between 50 and 500, which are divisible by 7.
Find the sum of all even integers between 101 and 999.
Find the sum of all natural numbers between 250 and 1000 which are divisible by 9.
Let there be an A.P. with first term 'a', common difference 'd'. If an denotes in nth term and Sn the sum of first n terms, find.
The common difference of the A.P.
The sum of first ten natural number is ______.
In an AP if a = 1, an = 20 and Sn = 399, then n is ______.
The 5th term and the 9th term of an Arithmetic Progression are 4 and – 12 respectively.
Find:
- the first term
- common difference
- sum of 16 terms of the AP.
