Find the sum of the first 25 terms of each of the arithmetic sequence below?21,32,43
Answers
Answered by
6
Given -
a = 21
d = a² - a¹
d = 32 - 21
d = 11
n = 25
we know the formula that,
sn = n/2{ 2a + (n-1)d}
Now,
sn = 25/2 {2 × 21 + (25 - 1) 11}
sn = 25/2 { 42 + 24 × 11}
sn = 25/2 (42 + 264)
sn = 25/2 × 306
sn = 25 × 153
sn = 3825
Hence,
Sum of 25th term of the AP is 3825.
a = 21
d = a² - a¹
d = 32 - 21
d = 11
n = 25
we know the formula that,
sn = n/2{ 2a + (n-1)d}
Now,
sn = 25/2 {2 × 21 + (25 - 1) 11}
sn = 25/2 { 42 + 24 × 11}
sn = 25/2 (42 + 264)
sn = 25/2 × 306
sn = 25 × 153
sn = 3825
Hence,
Sum of 25th term of the AP is 3825.
Similar questions