document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=195271>Question 195271</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Skydiving. If a skydiver jumps from an airplane at a<BR>\n" );
document.write( "height of 8256 feet, then for the first five seconds, her<BR>\n" );
document.write( "height above the earth is approximated by the formula<BR>\n" );
document.write( "h(t )16t2  8256. How many seconds does it take<BR>\n" );
document.write( "her to reach 8000 feet? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #146609 by </B><A HREF=/tutors/aboutme.mpl?userid=solver91311><B>solver91311(24713)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=solver91311><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=solver91311><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=146609\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font face=\"Garamond\" size=\"+2\">\r<BR>\n" );
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document.write( "Your height function is a bit askew.  If h(t) is to give you the height for a given time t, unless your skydiver is wearing a rocket pack that will make her height increase as time passes, then the height function has to be:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ h(t) = -16t^2 + 8256\">\r<BR>\n" );
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document.write( "What you need is to figure out what value of t will make h(t) = 8000, i.e.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ -16t^2 + 8256 = 8000\">\r<BR>\n" );
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document.write( "So just solve the quadratic for t.  Exclude any negative root -- quite obviously she didn't reach 8000 feet any time <i>before</i> she jumped, right?\r<BR>\n" );
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document.write( "John<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE e^{i\pi} + 1 = 0\"><BR>\n" );
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