Power of a point relative to a circle

### 26.10.7 Power of a point relative to a circle

Given a circle C of radius r and a point A at a distance of d from the center of C, the power of A relative to C is d2 − r2.

The powerpc command finds the power of a point relative to a circle.

- powerpc takes two arguments:
  - C, a circle.
  - P, a point.
- powerpc(C,P) returns the power of P relative to C.

#### Example

powerpc(circle(0,1+i),3+i)

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