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Fin sum of n terms of the series 1+4+11+26+57+120... ... . ..... ...
Fin sum of n terms of the series 1+4+11+26+57+120... ... . ..... ...

```
2 years ago

Chetan Jain
13 Points
```							The series is going in this way {(1-1)(2)+1}+{(2-1)(2)+2}+{(3-1)(2)+3}+..... Upto nth term,n means term no.So nth term is {(n-1)(2)+n}=3n-2So sum upto n terms = summation of 3n-2,n=1 to n∑3n-∑2 where n=1 to n=3∑n-2n{3.(n)(n+1)/2} -2nI hope you will understand
```
2 years ago
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• 101 Video Lectures
• Revision Notes
• Test paper with Video Solution
• Mind Map
• Study Planner
• NCERT Solutions
• Discussion Forum
• Previous Year Exam Questions