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Math Help - More ellispe- need help

  1. #1
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    More ellispe- need help

    Can you please help me with the following problems?

    Graph the ellipse.

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

    I got:



    4(x+1)^2 + 9(y-2)^2=36
    I divided all the terms by 36

    then I got: ((x+1)^2))/(4) + ((y-2)^2)/(4)=1
    the center is (-1,2)

    This is where I am stuck at and dont know what to do next or how to graph it.


    16(x-2)^2+4(y-1)^2=64
    I divided all the terms by 64

    then I got: ((x-2)^2)/(4) + ((y-1)^2)/(4)=1
    the center is (2,1)

    This is also where I get stuck.

    Find the foci of the ellipse whose equation is given

    ((x+3)^2)/(36)+ ((y-3)^2)/(25)=1

    I got: foci at (-3, +squareroot 11, 3) and (-3, -squareroot 11, 3)
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  2. #2
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    Hello, soly_sol!

    You're still making silly mistakes . . .


    Graph the ellipse: . \frac{(x-1)^2)}{9} + \frac{(y-2)^2}{4}\;=\;1

    I got:

    . . . No!
    The center is: . (1,\,2)



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

    I divided all the terms by 36: . \frac{(x+1)^2}{4} + \frac{(y-2)^2}{4}\;=\;1 . . . . No!
    \frac{4(x+1)^2}{36} + \frac{9(y-2)^2}{36} \;=\;\frac{36}{36}\quad\Rightarrow\quad \frac{(x+1)^2}{9} + \frac{y-2)^2}{4} \;=\;1
    This is where I am stuck at and dont know what to do next or how to graph it.
    If this is true, you need more help than we can give here.



    16(x-2)^2 + 4(y-1)^2\;=\;64

    I divided all the terms by 64: . \frac{(x-2)^2}{4} + \frac{(y-1)^2}{4}\;=\;1 . . . . Stop doing that!


    Find the foci of the ellipse: . \frac{(x+3)^2}{36} + \frac{(y-3)^2}{25} \;=\;1

    I got: foci at (-3, +squareroot 11, 3) and (-3, -squareroot 11, 3)
    . . . . . This doesn't make sense
    I assume you meant: . \left(-3,\;3+\sqrt{11}\right),\;\;\left(-3,\;3-\sqrt{11}\right)

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  3. #3
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    4(x+1)^2 + 9(y-2)^2=36
    I divided all the terms by 36

    I went back and corrected this one and this is the graph I got:



    16(x-2)^2+4(y-1)^2=64
    I divided all the terms by 64

    I went back and corrected this one and this is the graph I got:

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  4. #4
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    please check my answers.
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  5. #5
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    Quote Originally Posted by soly_sol View Post
    (A) 4(x+1)^2 + 9(y-2)^2=36
    I divided all the terms by 36

    I went back and corrected this one and this is the graph I got:



    (B) 16(x-2)^2+4(y-1)^2=64
    I divided all the terms by 64

    I went back and corrected this one and this is the graph I got:

    Hello,

    the lengthes(?) of the axes are OK but you forgot to calculate the coordinates of the centers of the ellipses:

    (A) C(-1, 2)

    (B) C(2, 1)

    With your graphs the centers are allways at the origin.
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