Advertisements
Advertisements
प्रश्न
Find the sum of first 20 terms of an A.P. whose first term is 3 and the last term is 57.
Advertisements
उत्तर
Here,
First term, a = 3
Last term, l = 57
n = 20
`S = n/2 (a + I)`
= `20/2 (3 + 57)`
= 10 × 60
= 600
APPEARS IN
संबंधित प्रश्न
The first term of an A.P. is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.
If (3y – 1), (3y + 5) and (5y + 1) are three consecutive terms of an AP then find the value of y.
The sum of the first n terms of an AP is `((5n^2)/2 + (3n)/2)`. Find the nth term and the 20th term of this AP.
Choose the correct alternative answer for the following question .
In an A.P. first two terms are –3, 4 then 21st term is ...
Divide 207 in three parts, such that all parts are in A.P. and product of two smaller parts will be 4623.
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)
Write the expression for the common difference of an A.P. whose first term is a and nth term is b.
The given terms are 2k + 1, 3k + 3 and 5k − 1. find AP.
First four terms of the sequence an = 2n + 3 are ______.
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.
