If (S_n=7n^2+2n) for an arithmetic progression, what is the sum from the (9)th to the (18)th terms?
Answer and explanation
Correct answer: (1840)
The required sum is (S_{18}-S_8=2304-464=1840). Exam tip: the sum from the (m)th to (n)th term is (S_n-S_{m-1}).
Frequently asked questions
What is the correct answer to this question?
(1840)
Why is this the correct answer?
The required sum is (S_{18}-S_8=2304-464=1840). Exam tip: the sum from the (m)th to (n)th term is (S_n-S_{m-1}).
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Arithmetic Progressions (AP). Topic: Finding the sum of the first $n$ terms of an AP.
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