👉 In mathematics, a biconical (or biconcave) curve is a type of curve that can be described as a combination of an ellipse and a circle. This means that it has both a curved shape and a straight line. An ellipse is a curve where all the points on the curve have the same distance from two fixed points called foci, whereas a circle is a plane curve with no thickness at any point. The biconcave curve can be thought of as an ellipse
