# Article

**Keywords:**

superconvergence; finite element method

**Summary:**

A method for the second-order approximation of the values of partial derivatives of an arbitrary smooth function $u=u(x_1,x_2)$ in the vertices of a conformal and nonobtuse regular triangulation $\mathcal T_h$ consisting of triangles and convex quadrilaterals is described and its accuracy is illustrated numerically. The method assumes that the interpolant $\Pi_h(u)$ in the finite element space of the linear triangular and bilinear quadrilateral finite elements from $\mathcal T_h$ is known only.