document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=972051>Question 972051</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I'm having a hard time with exponential functions. Here's the problem:\r<BR>\n" );
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document.write( "The radioactive bismuth isotope 210Bi has a half-life of 5 days. If there is 100 milligrams of 210Bi present at t=0, then the amount f(t) remaining after t days is given by f(t)=100(2)(^-t/5).\r<BR>\n" );
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document.write( "a. How much 210Bi remains after 5 days? 10days? 12.5 days?\r<BR>\n" );
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document.write( "b. Sketch the graph of f for 0<=t<=30.\r<BR>\n" );
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document.write( "Thank you!! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #594455 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=594455\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> f(5)=100*2^-(5/5)=50  That is just 1 half life and it is 100*2^-1 or 100/2<BR>\n" );
document.write( "f(10) is two half-lives, or half of a half.  That is 25.\r<BR>\n" );
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document.write( "f(12.5) is 100*2^-(2.5)=17.68 mg\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph+%28300%2C300%2C0%2C15%2C0%2C100%2C100%2A2%5E%28-x%2F2%29%29 ALIGN=MIDDLE  ALT=\"graph+%28300%2C300%2C0%2C15%2C0%2C100%2C100%2A2%5E%28-x%2F2%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >   y-axis by 10s; x-axis by 1 day </SPAN>\n" );
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