State the coordinates of the center and the measure of the radius
1. x^2 + y^2 - 4 = 0
2. X^2 + Y^2 + 6x = 6y + 9 = 0
circle equation is in the format (x – h)2 + (y – k)2 = r2, with the center being at the point (h, k) and r= radius
Put in standard form:
1 x^2 + y^2 = 4 4 = r^2 in this form so r = sqrt4 = 2 the cente is 0,0
#2 (I THINK that first = is supposed to be a +)
(x^2 +6x) + (Y^2+6y) = - 9 Complete the squares (do you know how to do this?)
(x^2 +6x +9) + (y^2+-6y +9) = -9 + 9 + 9
(x+3)^2 + (y+3)^2 = 9 Now it is in a standard form r^2 =9 r= sqrt9 = 3
the center is -3,-3
circle equation is in the format (x – h)2 + (y – k)2 = r2, with the center being at the point (h, k) and r= radius
Put in standard form:
1 x^2 + y^2 = 4 4 = r^2 in this form so r = sqrt4 = 2 the cente is 0,0
#2 (I THINK that first = is supposed to be a +)
(x^2 +6x) + (Y^2+6y) = - 9 Complete the squares (do you know how to do this?)
(x^2 +6x +9) + (y^2+-6y +9) = -9 + 9 + 9
(x+3)^2 + (y+3)^2 = 9 Now it is in a standard form r^2 =9 r= sqrt9 = 3
the center is -3,-3
