What is the center and radius of the circle with equation 36x^2 - 36x + 36y^2 - 24y = 13136x236x+36y224y=131?

1 Answer
Jan 29, 2016

The General equation of circle is : x^2 + y^2 + 2gx + 2fy + c = 0x2+y2+2gx+2fy+c=0

Explanation:

So,
Dividing all terms by 36 ( To remove the coefficient of x^2 and y^2)
We get,
x^2 - x + y^2 + 2/3 y = 131/36x2x+y2+23y=13136
Now
x^2 - x + y^2 + 2/3 y- 131/36 = 0x2x+y2+23y13136=0

Comparing the given equation with the general equation of circle we get,

2g = -11
or g = -1/212

Again,
2f = 2/323
or f = 1/313

And,

c= -131/3613136

Thus,
Center of the circle (h,k) = (-g ,-f g,f)
= (1/2 , -1/312,13)
And
Radius = sqrt(g^2+f^2-c)g2+f2c