document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=156348>Question 156348</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Trying to find the series for my son's \"Chicago Math\" 7th grade class. It's an exponetial series with the following (x,y) points (1,1), (2,3), (3,6), (4,10), (nth,?).\r<BR>\n" );
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document.write( "Help if you can, Thanks!  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #115156 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=115156\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> exponetial series with the following (x,y) points (1,1), (2,3), (3,6), (4,10), (nth,?<BR>\n" );
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document.write( "Exponential Form: y = ab^x<BR>\n" );
document.write( "You need to determine a and b.<BR>\n" );
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document.write( "Substitute x and y from any two points to get two equaitons:<BR>\n" );
document.write( "1 = ab^1<BR>\n" );
document.write( "6 = ab^3<BR>\n" );
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document.write( "Divide the 1st into the 2nd<BR>\n" );
document.write( "6 = b^2<BR>\n" );
document.write( "b = sqrt(6)<BR>\n" );
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document.write( "Substitute to solve for \"a\":<BR>\n" );
document.write( "1 = a(sqrt(6))^1<BR>\n" );
document.write( "a = 1/sqrt(6)<BR>\n" );
document.write( "a = 0.408248<BR>\n" );
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document.write( "EQUATION:<BR>\n" );
document.write( "y = (0.408248)(sqrt(6))^x<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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