document.write( "Question 1166292: In 1 and 2, do the following:
\n" ); document.write( " a) Write the equation of the parabola in standard form.
\n" ); document.write( " b) Find the vertex, focus, equation of the directrix and axis of symmetry of the parabola.
\n" ); document.write( "1. x^2-6x-5y-1=0
\n" ); document.write( "2. y^2-2y+3x-8=0\r
\n" ); document.write( "\n" ); document.write( "In 3 and 4, find an equation of the parabola that satisfies the given conditions. Express the answer in standard and general forms.
\n" ); document.write( "3. Vertex at V(-4,3),directrix at y=5.
\n" ); document.write( "4. Focus at F(-1,-5),directrix at x=-2.\r
\n" ); document.write( "\n" ); document.write( "5. Each cable of a suspension bridge is in the shape of a parabola and is supported by two towers at each end (refer to the figure below). The shape of the cable is modeled by the equation
\n" ); document.write( " x^2=200y
\n" ); document.write( "where x and y are measured in meters. Find the coordinates of the focus.\r
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Algebra.Com's Answer #790795 by greenestamps(13200)\"\" \"About 
You can put this solution on YOUR website!


\n" ); document.write( "One problem per post!!!

\n" ); document.write( "Here is all you need to work these problems yourself....

\n" ); document.write( "Vertex form of equation of a parabola that opens up or down:

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

\n" ); document.write( "Vertex form of equation of a parabola that opens right or left:

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

\n" ); document.write( "In both formulas, 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( "Here is a problem like your problems 1 and 2....

\n" ); document.write( "\"x%5E2-4x%2B4y=0\"

\n" ); document.write( "Complete the square in x and put the equation in vertex form.

\n" ); document.write( "\"%28x%5E2-4x%2B4%29%2B4y-4+=+0\"
\n" ); document.write( "\"%28x-2%29%5E2%2B4y-4=0\"
\n" ); document.write( "\"4y-4=%28x-2%29%5E2\"
\n" ); document.write( "\"4%28y-4%29=%28x-2%29%5E2\"
\n" ); document.write( "\"y-4=%281%2F4%29%28x-2%29%5E2\"

\n" ); document.write( "That is vertex form: h=2; k=4; 4p=4 so p=1.

\n" ); document.write( "The vertex is (h,k) = (2,4).

\n" ); document.write( "p=1, so the directed distance from the directrix to the vertex is 1, and the directed distance from the vertex to the focus is 1. That makes the directrix y=3 and the focus (2,5).

\n" ); document.write( "Your problem 5 is solved in a similar fashion.

\n" ); document.write( "For problems 3 and 4, use the definitions of (h,k) and p to write the equations.

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