document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=429014>Question 429014</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi, my son and I are having trouble figuring out his homework on \"series and sequences\". I don't know about you but I have never heard of that. Anyway these are the three problems:\r<BR>\n" );
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document.write( "1. Find the sum of the 1st 20 terms of the sequence 7,13,19...\r<BR>\n" );
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document.write( "2. Write the sum of the 1st n terms of the sequence -5,-2,1,...\r<BR>\n" );
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document.write( "3. How many terms of the sequence -19,-15,-11,... must be taken to give a sum of 98?\r<BR>\n" );
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document.write( "Thank you for your time and consideration! Your help is greatly appreciated. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #298068 by </B><A HREF=/tutors/aboutme.mpl?userid=richard1234><B>richard1234(7193)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richard1234><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=richard1234><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=298068\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A sequence is a collection of terms or objects in some order. For example, {4,7,10,13,...}, {6.4, pi, 8, -5,...} and {cat,dog,chicken,horse,...} can be considered sequences. A series is defined as the sum of the terms in a sequence.\r<BR>\n" );
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document.write( "For those three questions, use the formula <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%5Bn%5D+=+%28n%2F2%29%28a%5B1%5D+%2B+a%5Bn%5D%29 ALIGN=MIDDLE  ALT=\"S%5Bn%5D+=+%28n%2F2%29%28a%5B1%5D+%2B+a%5Bn%5D%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > where n is the number of terms in the arithmetic sequence, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%5Bn%5D ALIGN=MIDDLE  ALT=\"S%5Bn%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > is the sum of the first n terms, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5B1%5D ALIGN=MIDDLE  ALT=\"a%5B1%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > is the first term, and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5Bn%5D ALIGN=MIDDLE  ALT=\"a%5Bn%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > is the n-th term. I rarely see students try to memorize the formula, since it is often easier to re-derive it instead of memorize it (being able to derive the formula is also more advantageous than memorizing).\r<BR>\n" );
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