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Question
dont we have some ready-made formula for the questions which ask to find sum of a given series and the common difference between the terms is in. AP Normal summation method takes a lot of time
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Answer
Hi
If the differences are in A.P
then general term is of the form an^2+bn+c
You have to substitute the first three terms and solve simultaneous equations and obtain the values of a,b and c and then apply summation for each . This is the only approach for such questions .
