203k views
2 votes
Find the center and radius of circle x^2 + y^2 -12x + 2y + 33 = 0

User Arexx
by
8.3k points

2 Answers

4 votes

To find the center and radius of the circle given by the equation:

x^2 + y^2 -12x + 2y + 33 = 0

We need to rewrite the equation in standard form, which is:

(x - h)^2 + (y - k)^2 = r^2

where (h, k) is the center of the circle and r is the radius.

To do this, we need to complete the square for both x and y terms by adding and subtracting appropriate terms inside the parentheses.

(x^2 - 12x) + (y^2 + 2y) + 33 = 0

To complete the square for x terms, we need to add (12/2)^2 = 36 inside the first set of parentheses and subtract it from the equation:

(x^2 - 12x + 36) + (y^2 + 2y) + 33 - 36 = 0

(x - 6)^2 + (y^2 + 2y) - 3 = 0

To complete the square for y terms, we need to add (2/2)^2 = 1 inside the second set of parentheses and subtract it from the equation:

(x - 6)^2 + (y^2 + 2y + 1) - 4 = 0

(x - 6)^2 + (y + 1)^2 = 4

Now we can see that the equation is in standard form, where (h, k) = (6, -1) is the center of the circle, and r^2 = 4, so the radius is r = 2.

Therefore, the center of the circle is (6, -1) and the radius is 2.

5 votes

Answer:

To find the center and radius of the circle, we need to rewrite the equation in standard form, which is: (x - h)^2 + (y - k)^2 = r^2 where (h, k) is the center of the circle and r is the radius. To rewrite the given equation in standard form, we need to complete the square for both x and y terms. Let's start with the x terms: x^2 - 12x = -(y^2 - 2y + 33) To complete the square for x, we need to add and subtract (12/2)^2 = 36: x^2 - 12x + 36 - 36 = -(y^2 - 2y + 33) (x - 6)^2 - 36 = -(y^2 - 2y + 33) Now

User Sanjay Madnani
by
7.6k points