Summary: This article discusses the use of MathCAD software to solve differential equations of the first order.

Key words: mathematics еeditor, differential equations, Lagrange method.

Summary: we consider the different types of software that allow to make calculations for engineering and mathematical problems.  Their strengths and weaknesses  explored.

Key words: mathematics editor, finite elements method, engineering modeling.

Summary: The solution of the problem of stresses distribution in shells made of composite material with opening is given. The finite elements method was used. The influence of transversal shear on the stress concentration in the cylindrical transversely isotropic shell with circular opening was investigated.

Key words: stress, shell with circular opening, finite elements method.