document.write( "Question 1086398: find the area bounded by the curve x^2=8y and its latus rectum \n" ); document.write( "
Algebra.Com's Answer #700608 by math_helper(2461)\"\" \"About 
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The equation of the parabola can be written \"+y+=+%281%2F8%29x%5E2+\"
\n" ); document.write( "Graphed below (green line is latus rectum):
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+400%2C+400%2C+-4%2C+4%2C+-5%2C+5%2C+%281%2F8%29%2Ax%5E2%2C+y=2%29%0D%0A+\"\r
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\n" ); document.write( "\n" ); document.write( "For a (vertical) parabola with vertex @(h,k): \"+4p%28y-k%29+=+%28x-h%29%5E2+\"
\n" ); document.write( "Vertex is at (0,0) so h=k=0: so this parabola has equation \"+y+=+%281%2F8%29x%5E2+\"\r
\n" ); document.write( "\n" ); document.write( "Solve for p (the distance from vertex to focus) by comparison: \"+y+=+x%5E2%2F%284p%29+\" ==> \"+4p+=+8+\" ==> p=2
\n" ); document.write( "So focus is at (0,2). Latus rectum passed through (0,2) and intersects parabola where \"y+=+2+=+%281%2F8%29x%5E2+\" or (-4,2) and (4,2)\r
\n" ); document.write( "\n" ); document.write( "Using just the first quadrant & symmetry with 2nd quadrant:
\n" ); document.write( "Area = \"+2%2A+int%28%28+2+-+%281%2F8%29x%5E2%29%2C+dx%2C+0%2C+4%29+\"
\n" ); document.write( " = \"+2%2A+%282x+-+%281%2F24%29x%5E3%29+\" evaluated at 4 and 0
\n" ); document.write( " = \"+2%2A%28%288-%281%2F24%29%2864%29%29+-+%280-0%29%29+\"
\n" ); document.write( " = \"+highlight%2832%2F3%29+\"
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