Sign In
Use the discriminant of the equation by rewriting it in the form Ax^2+Bxy+Cy^2+Dx+Ey+F=0.
Circle
We want to state whether the graph of the given equation is a parabola, a circle, an ellipse, or a hyperbola. To do so, we will rewrite it in the form Ax^2+ Bxy+ Cy^2+ Dx+ Ey+ F=0. Then we can determine its discriminant. Recall that missing
terms have coefficient 0.
x^2 + y^2 - 8x - 6y + 5 = 0
⇕
1x^2 + 0xy + 1y^2 + ( - 8)x + ( - 6)y + 5=0
| Discriminant | Conic Section |
|---|---|
| B^2-4AC<0; B=0 and A=C | Circle |
| B^2-4AC<0; either B≠0 or A≠C | Ellipse |
| B^2-4AC=0 | Parabola |
| B^2-4AC>0 | Hyperbola |
Let's calculate the discriminant of our equation.
The discriminant is less than 0 and A = C, so the graph of the equation is a circle.