document.write( "Question 69247: I have some answers but im not sure if they are right. I need this by tonight, can you please help me?\r
\n" ); document.write( "\n" ); document.write( "1) Use the arithmetic sequence of numbers 2, 4, 6, 8, 10… to find the following:
\n" ); document.write( "a) What is d, the difference between any 2 terms?
\n" ); document.write( "Answer:
\n" ); document.write( "Show work in this space. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "b) Using the formula for the nth term of an arithmetic sequence, what is 101st term? Answer:
\n" ); document.write( "Show work in this space. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "c) Using the formula for the sum of an arithmetic sequence, what is the sum of the first 20 terms?
\n" ); document.write( "Answer: 430
\n" ); document.write( "Show work in this space.
\n" ); document.write( "You would add \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "d) Using the formula for the sum of an arithmetic sequence, what is the sum of the first 30 terms?
\n" ); document.write( "Answer: 960\r
\n" ); document.write( "\n" ); document.write( "Show work in this space. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "e) What observation can you make about the successive partial sums of this sequence (HINT: It would be beneficial to find a few more sums like the sum of the first 2, then the first 3, etc.)?
\n" ); document.write( "Answer: \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #49297 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
a)
\n" ); document.write( "The distance is the factor between each term. So going from 2 to 4, 4 to 6, 6 to 8, you see that its adding 2 each time. To verify pick one term and subtract the previous term from it. So lets say I choose 8: I'm going to subtract 6 from it to get a difference of 2. If I pick 6, and subtract 4, I get a difference of 2.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the distance (d) is\r
\n" ); document.write( "\n" ); document.write( "d=2\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "b)
\n" ); document.write( "Using what we found earlier, I know that the sequence counts up by 2 each term. So if I'm at 8 (the 4th term) then my nth term is 4 (if we started at n=1). If I let n=5 then the term is 10. So if I divide 10 by 5 then I get 2, which means the term is doubled. This basically tells me that the arithmetic sequence is 2n. To verify, simply plug in the 1st term (n=1) and you'll get 2. Plug in the 2nd term (n=2) you'll get 4, etc. If I wanted to know the 101st term, let n=101 and it comes to
\n" ); document.write( "\"2%2Ahighlight%28101%29=202\" So the 101st term is 202\r
\n" ); document.write( "\n" ); document.write( "c)
\n" ); document.write( "Using the sum of arithmetic series formula:
\n" ); document.write( "\"s=%28n%2F2%29%2A%28a%5B1%5D%2Ba%5Bn%5D%29\" a[1]=first term, a[n]=nth term, and n is nth term
\n" ); document.write( "\"s=%2820%2F2%29%2A%282%2B40%29\" Plug in values
\n" ); document.write( "\"s=%2810%29%2A%2842%29\"Simplify
\n" ); document.write( "\"s=420\" So the sum of the first 20 terms is 420 (A minor discrepancy with your answer, I'd like to know what you did to get 430)\r
\n" ); document.write( "\n" ); document.write( "d)
\n" ); document.write( "Again using the same formula
\n" ); document.write( "\"s=%28n%2F2%29%2A%28a%5B1%5D%2Ba%5Bn%5D%29\" a[1]=first term, a[n]=nth term, and n is nth term
\n" ); document.write( "\"s=%2830%2F2%29%2A%282%2B60%29\" Plug in values
\n" ); document.write( "\"s=%2815%29%2A%2862%29\"Simplify
\n" ); document.write( "\"s=930\" close but no cigar, maybe you added the same term twice?\r
\n" ); document.write( "\n" ); document.write( "e)
\n" ); document.write( "This one is a little tricky to explain, but the series (partial sums) follow the sequence \"n%2A%28n%2B1%29\" (try it out by picking n=1,n=2,n=3,etc). To make a long story short, this sequence is the sum of n even integers.
\n" ); document.write( "
\n" );