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Is 4x^2 + 4y^2 + 16x = 0 the equation of a circle.

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xetaalpha | Student | (Level 2) Honors

Posted March 24, 2012 at 3:13 PM via web

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Is 4x^2 + 4y^2 + 16x = 0 the equation of a circle.

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted March 24, 2012 at 3:20 PM (Answer #1)

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The standard equation of a circle with center (h, k) and radius r is (x - h)^2 + (y - )^2 = r^2

The equation of the curve given is 4x^2 + 4y^2 + 16x = 0

=> x^2 + y^2 + 4x = 0

=> x^2 + 4x + 4 + y^2 = 4

=> (x + 2)^2 + y^2 = 2^2

This is the equation of a circle with center (-2, 0) and radius 2.

4x^2 + 4y^2 + 16x = 0 is the equation of a circle with center (-2, 0) and radius 2

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