# The polar reciprocal: reciprocation

### 13.17.6 The polar reciprocal: reciprocation

The reciprocation command finds poles and polars.

- reciprocation takes two arguments:
  - C, a circle.
  - L, a list of points and lines.
- reciprocation(C,L) returns the list formed by replaced each point or line in L by its polar or pole with respect to the circle C.

#### Example.

Input:

reciprocation(circle(0,1),[point((1+i)/2),line(1,-1+i)])

Output: