document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=930791>Question 930791</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The mass of a radioactive substance follows a continuous exponential decay model, with a decay rate parameter of 8% per day. A sample of this radioactive substance has an initial mass of 2.01 kg Find the mass of the sample after two days. Round your answer to two decimal places.Note: This is a continuous exponential decay model.And though the decay rate parameter is 8%per day, the actual decay is not 8% each day. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #565283 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39617)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><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=565283\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Either this is exponential decay at 8% loss per day or it is not.  You need to know or decide which it is.\r<BR>\n" );
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document.write( "Start with <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=p%2Ae%5E%28-kt%29 ALIGN=MIDDLE  ALT=\"A=p%2Ae%5E%28-kt%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > if this is the kind of model wanted.  The variables are<BR>\n" );
document.write( "A, amount after passage of time t<BR>\n" );
document.write( "p, initial amount when t=0<BR>\n" );
document.write( "t, time passage in days<BR>\n" );
document.write( "e, base for the Natural Logarithm<BR>\n" );
document.write( "k, a constant\r<BR>\n" );
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document.write( "First, find the value for k using your 8% loss per day.<BR>\n" );
document.write( "For t=1, p=1, A=0.8.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%28A%29=ln%28p%29%2Bln%28e%5E%28-kt%29%29 ALIGN=MIDDLE  ALT=\"ln%28A%29=ln%28p%29%2Bln%28e%5E%28-kt%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%28A%29-ln%28p%29=-kt%2A1 ALIGN=MIDDLE  ALT=\"ln%28A%29-ln%28p%29=-kt%2A1\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=kt=ln%28p%29-ln%28A%29 ALIGN=MIDDLE  ALT=\"kt=ln%28p%29-ln%28A%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%28k=%281%2Ft%29%28ln%28p%2FA%29%29%29 ALIGN=MIDDLE  ALT=\"highlight_green%28k=%281%2Ft%29%28ln%28p%2FA%29%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Substitute the known or given values and evaluate k.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k=%281%2F1%29ln%281%2F0.8%29 ALIGN=MIDDLE  ALT=\"k=%281%2F1%29ln%281%2F0.8%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k=ln%281.25%29 ALIGN=MIDDLE  ALT=\"k=ln%281.25%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28k=0.223%29 ALIGN=MIDDLE  ALT=\"highlight%28k=0.223%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-<BR>\n" );
document.write( "The model for your example is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=p%2Ae%5E%28-0.223t%29 ALIGN=MIDDLE  ALT=\"A=p%2Ae%5E%28-0.223t%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >, or using your given initial quantity of material,  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28A=2.01e%5E%28-0.223t%29%29 ALIGN=MIDDLE  ALT=\"highlight%28A=2.01e%5E%28-0.223t%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >. </SPAN>\n" );
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