the sum of first 'a' terms of arithmetic progrenssion in given by formula Sn=3n²+n then it's 3rd term is
a)14 b)16 c)22 d)42
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Answered by
1
Answer:
16
Step-by-step explanation:
Sn= 3n²+n
S1= 3x1²+1 = 4
S2= 3x2²+2= 14
S3= 3x3²+3= 30
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Sn= 3n²+n
Term1 or T1 = 4 = S1
T2 = S2 - S1 = 14 - 4= 10
T3= S3 - S2 = 30- 14 = 16
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