Find the center and radius for the circle:
2x ^{2}+12x+2y ^{2}+12y+4=0

Question

Find the center and radius for the circle:
2x ^{2}+12x+2y ^{2}+12y+4=0

anonymous · Answer

$$2x ^{2}+12x+2y ^{2}+12y+4=0$$

anonymous · Answer

I am having trouble remembering the equations for this conic. How would you find the h and k to to solve for the radius, and how what equation do you use to find the center?

.sam. · Answer

The equation of a circle is
$$(x-a)^2+(x-b)^2=r^2$$

.sam. · Answer

The idea is to get in $(x-a)^2$ $(x-b)^2$ forms, we can use completing the square. Try start by factoring the 2 out of x and y

.sam. · Answer

$$2(x^2+6x)+2(y^2+6y)+4=0$$
Then complete the square for
(x^2+6x) and (y^2+6y)

anonymous · Answer

Thanks ^.^

.sam. · Answer

yw

anonymous · Answer

$$(x^2+6x)+(y^2+6y)=36$$ is this correct?

.sam. · Answer

Nope, do it carefully you'll get
$$2[(x+3)^2-9]+2[(y+3)^2-9]+4=0$$
Then
$$2 (x+3)^2+2 (y+3)^2-32=0$$