a1,a2,a3,........... ,an
This series is follow a rule if difference between two successive term is called common difference and all common difference of series is equal then called in A.P
Common difference=Next term - previous term
Common difference(सर्वांतर) is denoted by d
First term =a1
Second term=a2
d1=a2-a1
d2=a3-a2
If d1=d2
Then sequence is called in A.P
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