if the sum of first 4 terms is 10 and that of first 14 terms is 280, find the sum of its first n terms

Asked by nachiket arora | 11th Mar, 2011, 04:44: PM

Expert Answer:

Dear student,
 
Let a be the first term and d be the common difference of the AP.
 
Using the given information, we have:
We hope that clarifies your query.
 
Regards,
Team
TopperLearning

Answered by  | 11th Mar, 2011, 07:36: PM

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