A function of two

two-dimensional vectors, returning a

scalar. The slash product is the two-dimensional analogue of the

three-dimensional cross product.

Given two vectors

**a = [dx**_{a}, dy_{a}] and

**b = [dx**_{b}, dy_{b}]
**a / b = dx**_{b}dy_{a} - dx_{a}dy_{b}
The value of the slash product is always the magnitude of the vector returned by the cross product of equivalent three-dimensional vectors:

**a / b = |a| |b| sin θ**
where

**|b|** id the magnitude of vector

**a**,

**|b|** is the magnitude of vector

**b**, and

**θ** is the

angle which, applied to the

direction of vector

**a**, would produce the direction of vector

**b**.

This is also the area of a

parallelogram whose sides have the direction and magnitude of the two vectors, two sides for each vector.

It's very useful since

**|b| sin θ** is used for calculating the perpendicular distance from a point to a line segment.