### 26.12.7 Cartesian equation of a geometric object in the plane

See Section 27.10.5 for Cartesian equations of 3D objects.

The equation command finds the Cartesian equation for a geometric object.

- equation takes G, a geometric object.
- equation(G) returns the Cartesian equation in the variables x and y for G.

Note that x and y must be formal variables, you might need to purge them with with purge(x,y).

#### Example

equation(line(-1,i))

y=x+1 |  |  |  |  |  |  |  |  |  |