document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=959793>Question 959793</A>: <I><SPAN STYLE=\"word-break: break-all;\"> NASA launches a rocket at t=0 seconds. It's height, in meters above sea-level, as a function of time is given by h(t)= -4.9t^2+67t+339. How high above sea-level does the rocket get at it's peak? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #586612 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=586612\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> h(t)= -4.9t^2+67t+339<BR>\n" );
document.write( "The above is a \"quadratic\" (polynomial with a degree of 2).<BR>\n" );
document.write( "If it is a quadratic, then the graph is in the shape of a parabola.<BR>\n" );
document.write( "We know it opens downward because the coefficient associated with the x^2 term is negative (sad-face).<BR>\n" );
document.write( "Since it opens downwards, the vertex is the MAX.<BR>\n" );
document.write( "To find the 't' value of the vertex:<BR>\n" );
document.write( "t = -b/(2a)<BR>\n" );
document.write( "t = -67/(2*(-4))<BR>\n" );
document.write( "t = -67/(-8))<BR>\n" );
document.write( "t = 8.375 seconds.<BR>\n" );
document.write( ".<BR>\n" );
document.write( "to find the height, we plug into the original equation:<BR>\n" );
document.write( "h(8.375)= -4.9(8.375)^2+67(8.375)+339<BR>\n" );
document.write( "h(8.375) = 556.44 meters (answer) </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );