Question 38753
2, 4, 6, 8, 10…
b) Using the formula for the nth term of an arithmetic sequence, what is 101st term?
{{{n = a + (n-1)d}}}
{{{n = 2 + (100)(2)}}}
{{{n = 202}}}
c) Using the formula for the sum of an arithmetic series, what is the sum of the first 20 terms? 
{{{s = (n/2)(a + 20a)}}}
{{{s = (20/2)(42)}}}
{{{s = 420}}}
d) Using the formula for the sum of an arithmetic series, what is the sum of the first 30 terms?
{{{s = (n/2)(a + 30a)}}}
{{{s = (30/2)(62)}}}
{{{s = 930}}}
e) What observation can you make about these sums of this series (HINT: It would be beneficial to find a few more sums like the sum of the first 2, then the first 3, etc.)?
Well, we have the sums of first 20 and first 30, so I see the number greatly increasing as the sum of the higher numbers increases.