| Subject | English | Russian |
| math. | multiplying the first equation by | умножая первое уравнение на (p, the second by q; adding the relating equations and integrating; we obtain, after simplifying the right-hand term in the same way as in Sect.3) |
| math. | multiplying the first relation by 2 followed by summation, we come to the concise form of the above equation | последующее суммирование |
| math. | multiplying the first relation in 1 by x and the second one by y, followed by summation, we come to the concise form the above equations | с последующим суммированием |