The hyperbola is the locus of points on the plane whose difference of distances to two fixed points, foci, are constant.

Hyperbola Formula


Elements of the Hyperbola


The foci are the fixed points of the hyperbola. They are denoted by F and F'.

Transverse Axis or real axis

The tranverse axis is the line segment between the foci.

Conjugate Axis or imaginary axis

The conjuagate axis is the perpendicular bisector of the line segment Transverse Axis (transverse axis).


The center is the point of intersection of the axes and is also the center of symmetry of the hyperbola.


The points A and A' are the points of intersection of the hyperbola with the transverse axis.

Focal Radii

The focal radii are the line segments that join a point on the hyperbola with the foci: PF and PF'.

Focal Length

The focal length is the line segment Focal Length, which has a length of 2c.

Semi-Major Axis

The semi-major axis is the line segment that runs from the center to a vertex of the hyperbola. Its length is a.

Semi-Minor Axis

The semi-minor axis is a line segment which is perpendicular to the semi-major axis. Its length is b.

Axes of Symmetry

The axes of symmetry are the lines that coincide with the transversal and conjugate axis.


The asymptotes are the lines with the equations: Asymptote Equations

The Relationship Between the Semiaxes:

Relationship between Semiaxes

Eccentricity of a Hyperbola:

Eccentricity of a Hyperbola

Equation of the Hyperbola

Hyperbolas Centered at (0, 0)

Horizontal Transverse Axis

Horizontal Transverse Axis


F'(−c, 0) and F(c, 0)

Vertical Transverse Axis

Horizontal Transverse Axis


F'(0, −c) and F(0, c)

Hyperbolas Centered at (x0, y0)

Horizontal Transverse Axis


Hyperbolas Centered at the Origin

F(x0+c, y0) and F'(x0− c, y0)

By removing the denominators, an equation is obtained in the form:

Hyperbolas Centered at the Origin

Keep in mind that A and B have opposite signs.

Vertical Transverse Axis


Equation of the Hyperbola

F(x0, y0+c) and F'(x0, y0−c)

Rectangular Hyperbola

Rectangular Hyperbola

Hyperbolas where the semiaxes are equal are called rectangular or equilateral hyperbolas (a = b).

The equation of a rectangular hyperbola is:

Rectangular Hyperbola Equation

The equations of the asymptotes are:

Asymptotes Equation, Asymptotes Equation

That is, the angle bisectors of the quadrants.

The eccentricity is: Eccentricity

Equation of a Rectangular Hyperbola

Equilateral Hyperbola Rotated Rectangular Hyperbola

To switch the asymptotes to those determined by the x and y-axis, turn the asymptote −45° about the origin.

Rectangular Hyperbola

Rotated Rectangular Hyperbola

If it is rotated 45°, the hyperbola is in the second and fourth quadrant.

Rotated Rectangular Hyperbola