Answer
First three terms: $4,8,12$
last term: $400$
Sum of an arithmetic series: $20,200$
Work Step by Step
First three terms can be found as:$a_1=4(1)+0=4;a_2=8+0=8;a_3=12+0=12$
Last term can be found as: $a_{100}=400$
Sum of the an arithmetic series can be calculated by using formula $S_n=\dfrac{n}{2}(a_1+a_n)$
Here $n=40$
Thus,
$S_{100}=\dfrac{100}{2}(404)=20,200$
our results are:
First three terms: $4,8,12$
last term: $400$
Sum of an arithmetic series: $20,200$
