2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/107563We present some new results in theory of classical theta-functions of Jacobi and sigma-functions of Weierstrass: ordinary differential equations (dynamical systems) and series expansions. The paper is basically organized as a stream of new formulas.15 pages. v3 is in English (v1,2 are in Russian and the same)Classical Analysis and ODEsMathematical PhysicsDynamical SystemsExactly Solvable and Integrable Systemstext