Dick said:You complete the squares so you can write it in the form (x+a)^2+(y+b)^2=c. Do you know how to do that?
Dick said:Take the x part. You've got x^2-4x. If I add something to that it will become a perfect square of the form (x-a)^2. What's 'a'? What do you have to add?
Dick said:No, no. (x-a)^2=x^2-2ax+a^2, yes? If you match that up with x^2-4x, the 4 must be the 2a, as I see it. Think back to when you did this before.
kLownn said:Ohh, I see now.. so I just do the same thing for y?
Dick said:Sure.
kLownn said:Homework Statement
Find the centre and radius of the circle x²+y²-4x+2y+6=0
I have the solution. The circle is no defined because r² = -1 is impossible.
But... how do I even DO that equation to get the answer -1?!
No, it isn't. It is much better to actually do the "complete the square" rather than memorize formulas: so you don't make silly mistakes like that.icystrike said:it can actually be express as x²+y²+2fx+2gy+c=0
whrby C(-f,-g) and radius is [tex]\sqrt{g²+f²-c}[/tex]
HallsofIvy said:No, it isn't. It is much better to actually do the "complete the square" rather than memorize formulas: so you don't make silly mistakes like that.
The equation of a circle in standard form is (x - h)^2 + (y - k)^2 = r^2, where (h,k) is the center of the circle and r is the radius.
To find the center and radius of a circle given its equation, you can rewrite the equation in standard form and compare it to the general equation. The values of h and k will give the coordinates of the center, and the square root of r^2 will give the radius.
No, a circle cannot have a negative radius. A negative radius would imply that the circle is drawn in the opposite direction, which is not possible.
To find the length of an arc on a circle, you can use the formula L = rθ, where r is the radius and θ is the central angle in radians. If the angle is given in degrees, you can convert it to radians by multiplying by π/180.
A circle is a two-dimensional shape, while a sphere is a three-dimensional shape. A circle is formed by all the points on a plane that are equidistant from a central point, whereas a sphere is formed by all the points in space that are equidistant from a central point.