document.write( "Question 983883: The nth term of an arithmetical progression is n and the nth term is m. Find the first term and the common difference. \n" ); document.write( "
Algebra.Com's Answer #604898 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
TYPO!
\n" ); document.write( "\"The
\n" ); document.write( "nth term of an arithmetical progression is n and the
\n" ); document.write( "nth term is m.\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So, the nth term is n = m ,
\n" ); document.write( "and we do not have enough information about the rest of the arithmetic progression?
\n" ); document.write( "I guess the problem should read differently,
\n" ); document.write( "and I believe I am a good guesser,
\n" ); document.write( "but from so little information, all I can manage is some wild guesses.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "GUESS # 1:
\n" ); document.write( "Maybe it should read
\n" ); document.write( "\"The nth term of an arithmetical progression is n,
\n" ); document.write( "and the kth term is m.\"
\n" ); document.write( "Maybe with a number instead of k, or maybe k is m.
\n" ); document.write( "Then, with \"a%5B1%5D\" being the first term,
\n" ); document.write( "and \"d\" being the common difference,
\n" ); document.write( "\"a%5Bn%5D=a%5B1%5D%2Bd%2A%28n-1%29\"= the nth term, so \"n=a%5B1%5D%2Bd%2A%28n-1%29\" , and
\n" ); document.write( "\"a%5Bk%5D=a%5B1%5D%2Bd%2A%28k-1%29\"= the kth term, so \"m=a%5B1%5D%2Bd%2A%28k-1%29\" .
\n" ); document.write( "So
\n" ); document.write( "\"n-m=%28a%5B1%5D%2Bd%2A%28n-1%29%29-%28a%5B1%5D%2Bd%2A%28k-1%29%29\"
\n" ); document.write( "\"n-m=a%5B1%5D%2Bd%2A%28n-1%29-a%5B1%5D-d%2A%28k-1%29\"
\n" ); document.write( "\"n-m=d%2A%28n-1%29-d%2A%28k-1%29\"
\n" ); document.write( "\"n-m=d%2A%28n-1-%28k-1%29%29\"
\n" ); document.write( "\"n-m=d%2A%28n-1-k%2B1%29\"
\n" ); document.write( "\"n-m=d%2A%28n-k%29\"
\n" ); document.write( "\"highlight%28d=%28n-m%29%2F%28n-k%29%29\" and
\n" ); document.write( "\"System%28n=a%5B1%5D%2Bd%2A%28n-1%29%2Cd=%28n-m%29%2F%28n-k%29%29\"--->\"n=a%5B1%5D%2B%28%28n-m%29%2F%28n-k%29%29%2A%28n-1%29\"--->\"n=a%5B1%5D%2B%28n-m%29%2A%28n-1%29%2F%28n-k%29\"--->\"highlight%28a%5B1%5D=n-%28n-m%29%2A%28n-1%29%2F%28n-k%29%29\"
\n" ); document.write( "The resulting formula for \"a%5B1%5D\" is messy,
\n" ); document.write( "but I do not see a way to make it look simple.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "GUESS # 2:
\n" ); document.write( "Maybe it should read
\n" ); document.write( "\"The sum of the first n terms of an arithmetical progression is n,
\n" ); document.write( "and the nth term is m.\"
\n" ); document.write( "Then, with \"a%5B1%5D\" being the first term,
\n" ); document.write( "and \"d\" being the common difference,
\n" ); document.write( "the nth term is
\n" ); document.write( "\"a%5Bn%5D=a%5B1%5D=d%2A%28n-1%29=m\" , and
\n" ); document.write( "the sum of the first \"n\" terms is
\n" ); document.write( "\"n%2A%28a%5B1%5D%2Ba%5Bn%5D%29%2F2=n%2A%28a%5B1%5D%2Bm%29%2F2=n\" .
\n" ); document.write( "So,
\n" ); document.write( "\"n%2A%28a%5B1%5D%2Bm%29%2F2=n\"-->\"%28a%5B1%5D%2Bm%29%2F2=n%2Fn\"-->\"%28a%5B1%5D%2Bm%29%2F2=1\"-->\"a%5B1%5D%2Bm=2\"-->\"highlight%28a%5B1%5D=2-m%29\" , and
\n" ); document.write( "\"system%28a%5B1%5D%2Bd%2A%28n-1%29=m%2Ca%5B1%5D=2-m%29\"--->\"2-m%2Bd%2A%28n-1%29=m\"--->\"d%2A%28n-1%29=2m-2\"--->\"highlight%28d=%282m-2%29%2F%28n-1%29%29\" .
\n" ); document.write( "
\n" );