document.write( "Question 975420: Given the ellipse: 9x2 + 4y2 + 18x - 48y + 117 = 0 \r
\n" );
document.write( "\n" );
document.write( " a) Put the equation in standard form
\n" );
document.write( "
\n" );
document.write( " b) Horizontal or vertical major axis?
\n" );
document.write( "
\n" );
document.write( " c) Find center, vertices, foci,
\n" );
document.write( " length of major and minor axes,
\n" );
document.write( " and eccentricity \r
\n" );
document.write( "\n" );
document.write( "d) Sketch a graph of this ellipse.
\n" );
document.write( " \n" );
document.write( "
Algebra.Com's Answer #597200 by Boreal(15235)![]() ![]() You can put this solution on YOUR website! 9x2 + 4y2 + 18x - 48y + 117 = 0 \n" ); document.write( "Rewrite as \n" ); document.write( "9x^2 + 18x + ;;;; +4y^2 - 48 y =-117;; complete first square: 9(x^2+2x+1);; second 4(y^2-12y+36)\r \n" ); document.write( "\n" ); document.write( " 9(x^2+2x+1)+ 4(y^2-12y+36)=-117 + 9 +144 ;;remember to multiply the coefficient by the constant that was factored out\r \n" ); document.write( "\n" ); document.write( "9(x^2+2x+1)+ 4(y^2-12y+36)=36 ;;must divide both sides by 36 to make the right side 1.\r \n" ); document.write( "\n" ); document.write( "(x+1)^2/4 + (y-6)^2/9=1 \n" ); document.write( "Center is at (-1,6) \n" ); document.write( "Major axis is along y-axis. And it is a^2=9; a=3 Vertices are at (-1,3) and (-1,9) \n" ); document.write( "Minor axis is along x-axis. And it is b^2-4; b=2 These are at (1,6) and (-3,6) \n" ); document.write( "Foci are a^2-c^2=b^2 They are at sqrt (5) from center. (-1, 6+ sqrt (5)) and (-1, 6-sqrt (5)) \n" ); document.write( "Eccentricity is c/a which is sqrt(5)/3 \n" ); document.write( " |