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Math Help - standard form

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    standard form

    I need to put this equation 4x2 + 9y2 - 8x + 36y + 4 = 0. In the standard ellipsis form.
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    Quote Originally Posted by 14041471 View Post
    I need to put this equation 4x2 + 9y2 - 8x + 36y + 4 = 0. In the standard ellipsis form.
    Complete the square on the x and y terms...

    4x^2 - 8x + 9y^2 + 36y + 4 = 0

    4(x^2 - 2x) + 9(y^2 + 4y) + 4 = 0

    4[x^2 - 2x + (-1)^2 - (-1)^2] + 9[y^2 + 4y + 2^2 - 2^2] + 4 = 0

    4[(x - 1)^2 - 1] + 9[(y + 2)^2 - 4] + 4 = 0

    4(x - 1)^2 - 4 + 9(y + 2)^2 - 36 + 4 = 0

    4(x - 1)^2 + 9(y + 2)^2 - 36 = 0

    4(x - 1)^2 + 9(y + 2)^2 = 36

    \frac{(x - 1)^2}{9} + \frac{(y+2)^2}{4} = 1.
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  3. #3
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    Graph an Ellipsis

    Now I need to graph the Ellipsis whose equation is "4x2 + 9y2 - 8x + 36y + 4 = 0"
    This means plotting, the Foci,center,length of major and minor axis, but none of this really makes sense to me..please help
    Last edited by mr fantastic; January 12th 2009 at 03:37 PM. Reason: Moved from a new thread. Edited to make sense here.
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