document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=806717>Question 806717</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A stone is thrown directly upward from a height of 50 feet with an initial velocity of 56 ft/sec. The height of the stone \"t\" seconds after it has been thrown is given by the formula s(t)=-16t^2+56t+50. Use the appropriate algebraic formula to determine the time at which the ball reaches its maximum height and find what the maximum height is. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #485986 by </B><A HREF=/tutors/aboutme.mpl?userid=richwmiller><B>richwmiller(17219)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richwmiller><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=richwmiller><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=485986\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> s(t)=-16t^2+56t+50<BR>\n" );
document.write( "parabola<BR>\n" );
document.write( "focus | (7/4, 6335/64)=(1.75, 98.9844)<BR>\n" );
document.write( "vertex | (7/4, 99)~~(1.75, 99)<BR>\n" );
document.write( "semi-axis length | 1/64 = 0.015625<BR>\n" );
document.write( "focal parameter | 1/32 = 0.03125<BR>\n" );
document.write( "eccentricity | 1<BR>\n" );
document.write( "directrix | s = 6337/64<BR>\n" );
document.write( "vertex is the high point<BR>\n" );
document.write( "98.9844 ft at 1.75  seconds<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );