document.write( "Question 1047092: hi I am learning pre-calculus 11 and am stuck on this question thank you! \r
\n" ); document.write( "\n" ); document.write( "Q. Determine the sum, Sn, for each arithmetic sequence described.
\n" ); document.write( "a) T1=7, Tn=79, n=8 \r
\n" ); document.write( "\n" ); document.write( "they do not tell me what D is, so I am confused.. :)
\n" ); document.write( " \n" ); document.write( "
Algebra.Com's Answer #662585 by ikleyn(52790)\"\" \"About 
You can put this solution on YOUR website!
.
\n" ); document.write( "hi I am learning pre-calculus 11 and am stuck on this question thank you! \r
\n" ); document.write( "\n" ); document.write( "Q. Determine the sum, Sn, for each arithmetic sequence described.
\n" ); document.write( "a) T1=7, Tn=79, n=8 \r
\n" ); document.write( "\n" ); document.write( "they do not tell me what D is, so I am confused.. :)
\n" ); document.write( "~~~~~~~~~~~~~~~~~~~~\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\r\n" );
document.write( "There are two formulas for the sum of an arithmetic progression.\r\n" );
document.write( "\r\n" );
document.write( "The first formula is \r\n" );
document.write( "\r\n" );
document.write( "    \"S%5Bn%5D\" = \"T%5B1%5D+%2B+T%5B2%5D+%2B+T%5B3%5D+%2B+ellipsis+%2B+T%5Bn%5D\" = \"%28T%5B1%5D+%2B+%28n-1%29%2Ad%2F2%29%2An\". \r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "It really requires to know the \"d\", the common difference.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "But there is another formula for the sum of an arithmetic progression:\r\n" );
document.write( "\r\n" );
document.write( "    \"S%5Bn%5D\" = \"%28%28T%5B1%5D+%2B+T%5Bn%5D%29%2F2%29%2An\". \r\n" );
document.write( "\r\n" );
document.write( "for which to know \"T%5B1%5D\",  \"T%5Bn%5D\"  and  n  is enough.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "So, use this second formula, and you get\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "    \"S%5B8%5D\" = \"%28%28T%5B1%5D+%2B+T%5B8%5D%29%2F2%29%2A8\" = \"%28%287%2B79%29%2F2%29%2A8\" = 344.\r\n" );
document.write( "
\r
\n" ); document.write( "\n" ); document.write( "For arithmetic progressions, see the lessons \r
\n" ); document.write( "\n" ); document.write( "    - Arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - The proofs of the formulas for arithmetic progressions \r
\n" ); document.write( "\n" ); document.write( "    - Problems on arithmetic progressions \r
\n" ); document.write( "\n" ); document.write( "    - Word problems on arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - Chocolate bars and arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - Mathematical induction and arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - One characteristic property of arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - Mathematical induction for sequences other than arithmetic or geometric\r
\n" ); document.write( "\n" ); document.write( "    - Proving inequalities by the method of Mathematical Induction\r
\n" ); document.write( "\n" ); document.write( "    - Solved problems on arithmetic progressions \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "OVERVIEW of my lessons on arithmetic progressions with short annotations is in the lesson  OVERVIEW of lessons on arithmetic progressions.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );