Question 989971
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Arithmetic progression.
First term is 2.
The common difference is 2.
The number of terms is {{{(42-2)/2 + 1}}} = 21.


Use the formula for the sum (see the lesson <A HREF=http://www.algebra.com/algebra/homework/Sequences-and-series/Arithmetic-progressions.lesson>Arithmetic progressions</A> in this site)


S = {{{((a[1]+a[n])/2)}}}.{{{n}}} = {{{((2 + 42)/2)}}}.{{{21}}} = {{{44/2}}}.{{{21}}} = 22*21 = 462.