The focal length formula of hyperbola: focal length =2√(a-b). Eccentricity formula of hyperbola: e = √ (a-b)/a. Where a is the length of semi-major axis of ellipse and b is the length of semi-minor axis of ellipse. In mathematics, hyperbola is a conic curve, defined as two halves of a right-angled conic surface with intersecting planes. It can also be defined as the trajectory of a point whose distance difference from two fixed points (called focus) is constant. This fixed distance difference is twice that of A, where A is the distance from the center of hyperbola to the vertex of the nearest branch of hyperbola. A is also called the real semi-axis of hyperbola. The focal point is located on the through axis, and the middle point is called the center, which is generally located at the origin.