ὅδε οἶκος, ὦ ἑταῖρε, μνημεῖον ἐστιν ζῴων τῶν σοφῶν ἀνδρῶν, καὶ τῶν ἔργων αὐτῶν

Dimitrije Danić was born on January 21,1862 in Belgrade, and died on March 23,1932. He finished elementary school in Belgrade, secondary school in Zurich; then he completed three semesters at the Polytechnical School at Berlin and seven semesters at the Department of Natural Science and Mathematics of Berlin University, majoring in mathematics.

He defended his Ph. D. *Conformal Mapping of Elliptic Paraboloid on Plane* at Jena University, in 1885, where he also passed oral part of his doctoral examination. He applied for the post of lecturer of lower mathematical analysis at the Belgrade College for two times, in 1885 and in 1887, but was not accepted as full time professor. Disappointed, he left the Belgrade College and joined the Military Academy where, after only nine months, he was elected full time professor of mathematics, in December 1888. He was teaching at the Military Academy till his retirement.

Dimitrije Danić lectured all the courses in mathematics at the Military Academy, which, according to school curriculum were of the same quality as courses taught at the Belgrade College and later on at the University.

In his doctoral dissertation Dimitrije Danić considered conformal mapping of elliptic paraboloid to plane according to Gauss definition, i.e. the mapping of characteristic intersections of elliptic paraboloid for different forms of the function. In his work the author used differential and integral calculus for solving obtained differential equations. He had to solve complex elliptical integrals. His contribution is also in introducing elliptical transformations of variables and in using elliptical functions. He considered their interconnection, and connections with elliptical integrals. In the widest sense of its meaning, he used the theory of complex functions of complex variables.

Bearing in mind the time when this work was presented to the public and the level of development of mathematical analysis applied at the Belgrade College, then it could be concluded, without any doubt, that his dissertation represented significant contribution to the development of mathematics here.

He wrote eight textbooks and manuals:

*Formulas and Theorems in Trigonometry* (1888);* Analytical Geometry on Plane* (1893); *Lectures on Trigonometry with Theory of Logarithm and Complex Numbers *(1889); *Foundations of Infinitesimal Calculus Differential Calculus* (1920); *Foundations and Theory of Combination and Principles of Probability *(1921); *Foundations of Infinitesimal Calculus and Integral Calculus* (1922); *Analytical Geometry of Plane and Space* (1922);*Formulas and Theorems of Mathematics *(1927).

All those works consist of over 2.000 textbook pages. Some of the textbooks were a pioneering endeavor, as for example *Analytical Geometry of Plane and Analytical Geometry of Space*, or *Foundations of Theory of Combination and Principles of Probability*.

At the Military Academy, professor Danić was very strict professor, person of high criterium vis-a-vis his students. Besides his pedagogical work, he was interested in the problems of inner and outer ballistics of various arms and weapons. He was analysing the results of combat marksmanship, fire dispersion and marking of the target. In his analysis he applied his knowledge on Jacob Bernoulli's independent experiments.

For his distinguished achievements he was decorated with the Order of St.Sava of IV, III and II class.

Author: Vučićevoć, Radič