Advertisements
Advertisements
प्रश्न
For an A.P., If t1 = 1 and tn = 149 then find Sn.
Activitry :- Here t1= 1, tn = 149, Sn = ?
Sn = `"n"/2 (square + square)`
= `"n"/2 xx square`
= `square` n, where n = 75
उत्तर
Here, t1= 1, tn = 149, Sn = ?
Sn = `"n"/2 ("t"_1 + "t"_"n")`
= `"n"/2 (1 + 149)`
= `"n"/2 xx 150`
= 75 n, where n = 75
APPEARS IN
संबंधित प्रश्न
Find the sum of the following APs.
0.6, 1.7, 2.8, …….., to 100 terms.
Find the sum given below:
–5 + (–8) + (–11) + ... + (–230)
Find the sum of the following arithmetic progressions
`(x - y)^2,(x^2 + y^2), (x + y)^2,.... to n term`
How many terms of the A.P. 63, 60, 57, ... must be taken so that their sum is 693?
Find the sum of the first 40 positive integers divisible by 5
Find the value of x for which (x + 2), 2x, ()2x + 3) are three consecutive terms of an AP.
If k,(2k - 1) and (2k - 1) are the three successive terms of an AP, find the value of k.
If the sum of first n terms is (3n2 + 5n), find its common difference.
The sum of the first n terms in an AP is `( (3"n"^2)/2 +(5"n")/2)`. Find the nth term and the 25th term.
Find the sum of all natural numbers between 200 and 400 which are divisible by 7.
Find the first term and common difference for the A.P.
127, 135, 143, 151,...
Kargil’s temperature was recorded in a week from Monday to Saturday. All readings were in A.P. The sum of temperatures of Monday and Saturday was 5°C more than sum of temperatures of Tuesday and Saturday. If temperature of Wednesday was –30° celsius then find the temperature on the other five days.
If S1 is the sum of an arithmetic progression of 'n' odd number of terms and S2 the sum of the terms of the series in odd places, then \[\frac{S_1}{S_2} =\]
If Sn denote the sum of the first n terms of an A.P. If S2n = 3Sn, then S3n : Sn is equal to
Q.13
The sum of first 14 terms of an A.P. is 1050 and its 14th term is 140. Find the 20th term.
Find the sum of first 20 terms of an A.P. whose first term is 3 and the last term is 57.
In an A.P. (with usual notations) : given a = 8, an = 62, Sn = 210, find n and d
Find the sum of the integers between 100 and 200 that are not divisible by 9.
Find the value of a25 – a15 for the AP: 6, 9, 12, 15, ………..
