R: Intersection of two circumferences

inter {alphahull} | R Documentation

## Intersection of two circumferences

### Description

This function calculates the intersection of two circumferences, given their centers and radius c1,r1 and c2,r2, respectively.

### Usage

    inter(c11, c12, r1, c21, c22, r2)

### Arguments

`c11` | X-coordinate of the center c1.
`c12` | Y-coordinate of the center c1.
`r1` | Radius r1.
`c21` | X-coordinate of the center c2.
`c22` | Y-coordinate of the center c2.
`r2` | Radius r2.

### Details

The function `inter` is internally called by the function `ahull`.

### Value

A list with the following components:

`n.cut` | Number of intersection points (0,1,2, or Inf).
`v1` | If there are two intersection points, `v1` is the numeric vector whose components are the coordinates of the unitary vector that has its origin in c1 and it's perpendicular to the chord that joins the intersection points of the two circumferences. Otherwise, `v1=(0,0)`
`theta1` | Angle that forms `v1` with the radius that joins the center c1 with an intersection point.
`v2` | If there are two intersection points, `v2` is the numeric vector whose components are the coordinates of the unitary vector that has its origin in c2 and it's perpendicular to the chord that joins the intersection points of the two circumferences. Otherwise, `v2=(0,0)`
`theta2` | Angle that forms `v2` with the radius that joins the center c2 with an intersection point.

[Package alphahull version 2.2 Index]