document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=418542>Question 418542</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The number of Facebook members from the start of 2006 to mid-2008 can be approximated by<BR>\n" );
document.write( "S(t) = 15t2 &#8722; 76t + 101 million members  (2 &#8804; t &#8804; 4.5)<BR>\n" );
document.write( "in year t (t = 0 represents the start of 2004).<BR>\n" );
document.write( "[Source: www.facebook.com/, http://insidehighered.com (Some data are interpolated.)]<BR>\n" );
document.write( "(a) Compute S'(t).<BR>\n" );
document.write( "S'(t)	= 	<BR>\n" );
document.write( "1\r<BR>\n" );
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document.write( "According to the model, how fast was Facebook membership changing at the start of 2008 (t = 4)? (Be careful to give correct units of measurement.)<BR>\n" );
document.write( "S'(4)	= 	2 million members per year<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 #292915 by </B><A HREF=/tutors/aboutme.mpl?userid=richard1234><B>richard1234(7193)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richard1234><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=richard1234><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=292915\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> S'(t) = 30t - 76 (million members per year), by the power rule.\r<BR>\n" );
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document.write( "When t = 4, S'(t) = 30(4) - 76 = 44 million members per year. </SPAN>\n" );
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