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Math Help - Find Radius and Center of Sphere

  1. #1
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    Find Radius and Center of Sphere

    Find radius and center of sphere.

    3x^2 + 3y^2 + 3z^2 + 6x - 6y = 3
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    Moo
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    Hello,
    Quote Originally Posted by magentarita View Post
    Find radius and center of sphere.

    3x^2 + 3y^2 + 3z^2 + 6x - 6y = 3
    Do you know what the equation of a sphere is ?

    (x-x_0)^2+(y-y_0)^2+(z-z_0)^2=r^2

    Center (x_0,y_0,z_0) and radius r.

    Divide by 3 :
    x^2+y^2+z^2+2x-2y=1

    (x^2+2x)+(y^2-2y)+z^2=1

    Complete the squares for the stuff in the brackets.
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    Smile ok............

    Quote Originally Posted by Moo View Post
    Hello,

    Do you know what the equation of a sphere is ?

    (x-x_0)^2+(y-y_0)^2+(z-z_0)^2=r^2

    Center (x_0,y_0,z_0) and radius r.

    Divide by 3 :
    x^2+y^2+z^2+2x-2y=1

    (x^2+2x)+(y^2-2y)+z^2=1

    Complete the squares for the stuff in the brackets.
    Very good notes and tips.
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