document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=616029>Question 616029</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If you're given \r<BR>\n" );
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document.write( "x^2/25+y^2/16=1<BR>\n" );
document.write( "What is the foci? \r<BR>\n" );
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document.write( "Given 36x^2+9y^2-324=0<BR>\n" );
document.write( "Find the<BR>\n" );
document.write( "center:<BR>\n" );
document.write( "vertices:<BR>\n" );
document.write( "co-vertices:<BR>\n" );
document.write( "foci: I know it's c^2=a^2+b^2 or subtraction?\r<BR>\n" );
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document.write( "Sorry, These questions I have trouble with on the review, please help! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #387461 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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=387461\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x^2/25+y^2/16=1<BR>\n" );
document.write( "What is the foci? <BR>\n" );
document.write( "This is an equation of an ellipse with horizontal major axis<BR>\n" );
document.write( "Its standard form: (x-h)^2/a^2+(y-k)^2/b^2=1, (a>b), (h,k)=(x,y) coordinates of the center<BR>\n" );
document.write( "For given equation:<BR>\n" );
document.write( "center: (0,0)<BR>\n" );
document.write( "a^2=25<BR>\n" );
document.write( "b^2=16<BR>\n" );
document.write( "c^2=a^2-b^2=25-16=9<BR>\n" );
document.write( "c=&#8730;9=3<BR>\n" );
document.write( "foci: (0±c,0)=(0±3,0)=(-3,0) and (3,0)<BR>\n" );
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document.write( "Given 36x^2+9y^2-324=0<BR>\n" );
document.write( "36x^2+9y^2=324<BR>\n" );
document.write( "divide by 324<BR>\n" );
document.write( "x^2/9+y^2/36=1<BR>\n" );
document.write( "This is an ellipse with vertical major axis<BR>\n" );
document.write( "center: (0,0)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "a^2=36<BR>\n" );
document.write( "a=&#8730;36=6<BR>\n" );
document.write( "vertices:(0,0±a)=(0,0±6)=(0,-6) and (0,6)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "b^2=9<BR>\n" );
document.write( "b=3<BR>\n" );
document.write( "co-vertices:(0±b,0)=(0±3,0)=(-3,0) and (3,0)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "c^2=a^2-b^2=36-9=25<BR>\n" );
document.write( "c=&#8730;25=5<BR>\n" );
document.write( "foci:(0,0±c)=(0,0±5)=(0,-5) and (0,5) </SPAN>\n" );
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