Problem 737

Find the sum of the first five terms of the arithmetic series:

an = 2n +2.

 

Solution:-

 

Find a1 and  a5  and use the formula for the sum of an arithmetic series:    Sn = \frac{n}{2} (a1 + an)

a1 = 2* 1 + 2 = 4

a5 =2*5 +2 = 12

Sn = 40

 

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