document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=58915>Question 58915</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Locating the receiver for a radio telescope.<BR>\n" );
document.write( "The U.S. Naval research Laboratory designed a giant radio telescope weighting 3450 tons. Its parabolic dish has a diameter of 300 feet and a depth of 44 feet<BR>\n" );
document.write( "(a) find an equation in the form y=ax^2 that describes a cross section of this dish.<BR>\n" );
document.write( "(b) if the receiver is located at the focus, how far should it be from the dish(vertex)? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #40417 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=40417\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The U.S. Naval research Laboratory designed a giant radio telescope weighting 3450 tons. Its parabolic dish has a diameter of 300 feet and a depth of 44 feet<BR>\n" );
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document.write( "(a) find an equation in the form y=ax^2 that describes a cross section of this dish.\r<BR>\n" );
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document.write( "Draw the parabolic cross section on a coordinate system.<BR>\n" );
document.write( "Vertex at (0,-44); x-intercepts at (-150,0) and (150,0)<BR>\n" );
document.write( "Form: (x-h)^2=4p(y-k)<BR>\n" );
document.write( "h=0; k=-44; x=150; y=0<BR>\n" );
document.write( "150^2=4p(44)<BR>\n" );
document.write( "p=127.84<BR>\n" );
document.write( "EQUATIOn:<BR>\n" );
document.write( "x^2=4(127.84)(y+44)<BR>\n" );
document.write( "y=(1/511.36)x^2 - 44<BR>\n" );
document.write( "y=0.0019555695...x^2 -44<BR>\n" );
document.write( "----------------------------\r<BR>\n" );
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document.write( "(b) if the receiver is located at the focus, how far should it be from the dish(vertex)?<BR>\n" );
document.write( "Focus at (0,p) = (0,127.84 ft.)<BR>\n" );
document.write( "127.84 ft above the vertex<BR>\n" );
document.write( "-------------<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
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