document.write( "Question 1119528: Find the focus, vertex, length of latus rectum,and the equation of directrix of the parabola y^2 - 10x = 0 \n" ); document.write( "
Algebra.Com's Answer #735138 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "The equation has a y^2 term, so the parabola opens right or left. Vertex form for the equation of a parabola that opens right or left is

\n" ); document.write( "\"x-h+=+%281%2F%284p%29%29%28y-k%29%5E2\"

\n" ); document.write( "where the vertex is (h,k) and p is the directed distance from the directrix to the vertex and from the vertex to the focus.

\n" ); document.write( "Note with this form of the equation, the length of the latus rectum (perpendicular to the axis of symmetry and through the focus) is |4p|.

\n" ); document.write( "Put the given equation in that form:

\n" ); document.write( "\"y%5E2-10x+=+0\"
\n" ); document.write( "\"10x+=+y%5E2\"
\n" ); document.write( "\"x+=+%281%2F10%29y%5E2\"
\n" ); document.write( "\"x-0+=+%281%2F10%29%28y-0%29%5E2\"

\n" ); document.write( "This is in vertex form. The vertex is (0,0); p = 10/4 = 2.5.

\n" ); document.write( "vertex: (0,0)
\n" ); document.write( "focus: p = 2.5 right of the vertex, at (2.5,0)
\n" ); document.write( "directrix: p = 2.5 left of the vertex; x = -2.5
\n" ); document.write( "length of latus rectum: 4p = 10
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