Question

the sum of series of nth term is 7n²+1 find its first term and 100 term​

Answer 1

Answer:

Sum of first term=first term

Sn=7n²+1

S₁=7(1)²+1=a

a=7+1=8

S₂=a+a₂=2a+d

7(2)²+1=2(8)+d

29=16+d

29-16=d=13

a₁₀₀=a+99d=8+99*13

a₁₀₀=8+1287=1295

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