document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1110215>Question 1110215</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given the sequence 3;6;9;.....;60.\r<BR>\n" );
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document.write( "a)Determine the number of terms in the sequence\r<BR>\n" );
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document.write( "b)Determine the sum of the terms in the sequence </SPAN>\n" );
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document.write( "a) The numbers are the first 20 multiples of 3; so the number of terms in the sequence is 20.<br><BR>\n" );
document.write( "More formally...<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=60-3+=+57 ALIGN=MIDDLE  ALT=\"60-3+=+57\"   DISABLED_style= \"max-width:90%; height:auto;\" >  difference between first and last terms<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=57%2F3+=+19 ALIGN=MIDDLE  ALT=\"57%2F3+=+19\"   DISABLED_style= \"max-width:90%; height:auto;\" >  divide by common difference to find the number of terms AFTER THE FIRST TERM<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=19%2B1+=+20 ALIGN=MIDDLE  ALT=\"19%2B1+=+20\"   DISABLED_style= \"max-width:90%; height:auto;\" >  you need to count the first term also<br><BR>\n" );
document.write( "b) Since this is an arithmetic sequence (common difference between successive terms), the average of all the numbers is the average of the first and last.<br><BR>\n" );
document.write( "Since in ANY set of numbers the sum is equal to the average multiplied by the number of numbers, the sum of the terms in this sequence is<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28%283%2B60%29%2F2%29%2A20+=+63%2A10+=+630 ALIGN=MIDDLE  ALT=\"%28%283%2B60%29%2F2%29%2A20+=+63%2A10+=+630\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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