document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=417867>Question 417867</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am trying to find the interest rate \"r\" in this problem:<BR>\n" );
document.write( "\"At a certain constant APR over the life of the investment, Mara’s $2,000 investment grew to <BR>\n" );
document.write( "$3,000 in eight years. Determine that nominal annual rate of interest (APR), knowing that the <BR>\n" );
document.write( "interest rate was constant for those eight years and that interest was compounded annually.\" <BR>\n" );
document.write( "I am using the equation:<BR>\n" );
document.write( "A=P(1+r)^t<BR>\n" );
document.write( "A being the final investment value, P being the initial investment value, r being the interest rate, and t being the amount of time.<BR>\n" );
document.write( "I have gotten as far as this:<BR>\n" );
document.write( "0.5 = r^8<BR>\n" );
document.write( "I understand that to solve this, I need to use a logarithm, and so I translated it into:<BR>\n" );
document.write( "8=log(r) 0.5<BR>\n" );
document.write( "but I can't figure out how to solve for \"r\" after that.  <BR>\n" );
document.write( "Thank you!<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #292508 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=292508\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 3000 = 2000 (1 + r)^8\r<BR>\n" );
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document.write( "1.5 = (1 + r)^8\r<BR>\n" );
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document.write( "log(1.5) = 8 [log(1 + r)]\r<BR>\n" );
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document.write( "[log(1.5)] / 8 = log(1 + r)\r<BR>\n" );
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document.write( "1 + r = 10^{[log(1.5)] / 8} ___ this is the inverse of the logarithm operation </SPAN>\n" );
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