Question

Find the sum of the first 42 terms of the following series, to the nearest

Answer 1

Answer:

Step-by-step explanation:

Find the sum of the first 42 terms of the following series, to the nearest integer.

2,7,12

Solution

The sum is given by  

SUM_n=n/2*(a_1+a_n)

a_n=a_1+(n-1)d

a_1=2,   n=42,     d=5

The 42nd term is therefore given by  

a_42=2+(42-1)5=207

SUM_42=42/2*(2+207)=21*209=4389

The sum of the first 42 terms of the series, therefore, is 4389