Modular Trigonometry

The modular trigonometric functions - analogs of the usual trigonometric function in the truncated polynomial algebra over the field of positive characteristics - were constructed and properties of these functions were studied; analogs of the Euler-s and Moivre-s formulas were obtained as well as modular trigonometric form of the truncated polynomials; some examples of Fourier-s decomposition of truncated polynomials were obtained; one-parametric subgroups of the truncated polynomial algebra were classified.