Graph the ellipse x^2+4y^2=64

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embizze | High School Teacher | (Level 1) Educator Emeritus

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Graph `x^2+4y^2=64` :

The standard form for an ellipse is `(x-h)^2/a^2+(y-k)^2/b^2=1` where the center of the ellipse is at (h,k). If a>b then the major axis of the ellipse is horizontal; if b>a the major axis is vertical.

Dividing by 64 we get:

`x^2/64+y^2/16=1`  Since 64>16 the major axis is horizontal.

The length of the major axis is 2a; in this case it is 16. The length of the minor axis is 2b -- in this case 8. The center of the ellipse is at (0,0).

So the points (8,0),(-8,0),(0,4),(0,-4) lie on the ellipse. An easy way to sketch the ellipse is to lightly pencil in the rectangle formed by x=8,x=-8,y=-4,y=4; then sketch the ellipse inscribed in the recatangle.

The graph:

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oldnick | (Level 1) Valedictorian

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`x^2+4y^2=64`  dividing for 64 we get:


`x^2/64+y^2/16=1`    ellipse of axis  `a=8`  and `b=4`

Expilict form:    `y=1/2sqrt(64-x^2)`

 

`y=0`    `x= +-8`      `x=0`   `y=+-4`

 

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