# Mathematical name of time dilation curve

1. Aug 16, 2014

### HALON

In mathematics, what is the name (type) for a curve given by velocity and time dilation?

Specifically, I want to find a name for the curve $y=1/(1-x^2)^{1/2}$

This curve is derived from the equation of a unit circle $(x-a)^2+(y-b)^2=r^2$
where $y=(1-x^2)^{1/2}$

2. Aug 17, 2014

### Simon Bridge

It's called a hyperbola. Well - sort of.

The general equation is: $(x^2-h)(y^2-k)=m$

Your relation has $k=0, h=-1, m=-1$

This is a rectangular hyperbola in $(x^2,y^2)$

You can get much more general than that by just taking the product of two polynomials... $$P_n(x)P_m(y)=\text{const.}$$

Last edited: Aug 17, 2014