The aim of the research is to show based on concrete case studies the application of the scientific approach in tax planning. That tax planning and optimization are finding ways to reduce tax payments, and at the same time have a role in achieving tax savings through various opportunities for tax relief and other savings. Research of existing Croatian practice through appropriate case studies will confirm the thesis Specific and specialized knowledge as well as being familiar with them. Besides direct costs, taxīurdens also create indirect costs because increasingly complex tax regulations demand Tax expense makes up a significant part of the company’s total costs, which areĭirectly related to the company’s competitiveness on the market. Two illustrative examples are presented to demonstrate the simplicity of the developed second-order MSA approach for a systematic analysis of imperfect frames. The established formulations and the intuitive plots are readily coded in an easy-to-use computer program given in the Appendix for analyzing the exact second-order effect of general frames with initial imperfections and intermediate loads. Some intuitive plots of the fixed-end force vector are presented for convenient applications to typical engineering situations. The equilibrium relationship between the element-end displacements and forces is developed in a matrix form, which includes a second-order element stiffness matrix and the fixed-end force vector. Based on the equilibrium analysis of an imperfect axial-loaded beam–column, the element-end displacements and forces are solved exactly from the governing differential equation. To develop the second-order MSA method, the fixed-end force vector is formulated in simplified forms to account for the effect of the member initial imperfections and the intermediate loads. Based on the matrix structural analysis (MSA), this paper presents a method for the exact second-order solutions of imperfect frame structures, which allows the use of one element per member for the exact solution. Initial member imperfections play important roles in the second-order effect of structures, and thus it is helpful to find ways for engineers to easily model the member imperfections in the analysis.