On symmetry of projective curves

The known methods to find symmetry for convex ovals have been extended for a new class of plane projective curves, including real cubic curves. The proposed method uses only the description of tangent lines, but does not require the calculation of the curvature. This approach increases the accuracy of the calculations and allows you to use graphical methods. The recognition of symmetrically arranged points allows to coordinate pictures taken from different angles, as we study the symmetry of projective curves. The results can be used to illustrate the methods of descriptive geometry.