document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=821496>Question 821496</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The effectiveness of a drug is given by the formula N=250e-a/100 t where N is the number of effective particles and t is the time in years. Plot a graph of N againsr t from o to 5 years. Determine by calculation the half life of the drug ( the time it takes for the drug to have half the original number of effective particles) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #494165 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=494165\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The effectiveness of a drug is given by the formula N=250e^((-a/100)t) where N is the number of effective particles and t is the time in years. Plot a graph of N againsr t from o to 5 years. Determine by calculation the half life of the drug ( the time it takes for the drug to have half the original number of effective particles)<BR>\n" );
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document.write( "Note: Can't plot a graph with that \"a\" in the formula.<BR>\n" );
document.write( "Have to know what \"a\" is.<BR>\n" );
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document.write( "N(2) = 250e^((-a/100)t)<BR>\n" );
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document.write( "Solve e^(-a/100)t = 1/2<BR>\n" );
document.write( "Take the natural log of both sides::<BR>\n" );
document.write( "(-a/100)t = ln(1/2)<BR>\n" );
document.write( "Note: Can't solve that with that \"a\" in there.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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