Special Series
The sum 1 + 2 + 3 + ... + n equals
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About This Question
- Subject
- mathematics
- Chapter
- sequence and series
- Topic
- special series
- Difficulty
- Easy
- Year
- 2025
Solution
Correct Answer:
n(n+1)/2
- Identify the Series: This is an AP with a=1,d=1, and last term l=n.
- Apply Sum Formula: Sn=2n(a+l).
- Substitution:
- Sn=2n(1+n)=2n(n+1).
- Conclusion: This gives the sum of the first n natural numbers.
This easy difficulty mathematics question is from the chapter sequence and series, covering the topic of special series. It appeared in the 2025 exam.
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