Heart Curve
There are a number of mathematical curves that produced heart shapes, some of which are illustrated above. A "zeroth" curve is a rotated cardioid (whose name means "heart-shaped") given by the polar equation
| r(theta)=1-sintheta. |
(1)
|
The first heart curve is obtained by taking the y=0 cross section of the heart surface and relabeling the z-coordinates as y, giving the order-6 algebraic equation
| (x^2+y^2-1)^3-x^2y^3=0. |
(2)
|
A second heart curve is given by the parametric equations
where t in [-1,1] (H. Dascanio, pers. comm., June 21, 2003).
A third heart curve is given by
(P. Kuriscak, pers. comm., Feb. 12, 2006). Each half of this heart curve is a portion of an algebraic curve of order 6.
A fourth curve is the polar curve
due to an anonymous source and obtained from the log files of Wolfram|Alpha in early February 2010. Each half of this heart curve is a portion of an algebraic curve of order 12, so the entire curve is a portion of an algebraic curve of order 24.
A fifth heart curve can be defined parametrically as
A sixth heart curve is given by the simple expression
| x^2+[y-(x^2)^(1/3)]^2=1, |
(9)
|
(noted on a greeting card by J. Schroeder, pers. comm., Oct. 16, 2021). When properly nondimensionalized with scale parameters a and b, the curve becomes
which can be written as a sextic equation in x and y.
A seventh heart curve can be defined parametrically as
which arises through modifying the parametric equations of a nephroid (J. Mangaldan, pers. comm., Feb. 14, 2023).
The areas of these hearts are
where A_4 can be given in closed form as a complicated combination of hypergeometric functions, inverse tangents, and gamma functions.
The Bonne projection is a map projection that maps the surface of a sphere onto a heart-shaped region as illustrated above.
See also
Bonne Projection, Cardioid, Heart Surface, Watt's CurveExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Heart Curve." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/HeartCurve.html