решение. 1. ri=2*r; rii=r/2; ri/rii=4; не надо ни о какой площади сечения говорить. два куска проволоки содинили последовательно, получили ri=2*r; два куска той же проволоки соединили параллельно, получили rii=r/2; ну, а теперь раздели первое на второе!
а теперь общий случай: ri=r*n; rii=r/n; ri/rii=n^2; кусок проволоки разрезали на n одинаковых кусков. сначала эти куски соединяют последовательно: ri=r*n; затем соединяют параллельно rii=r/n; ну и дели первое на второе и делай выводы.
Vitebsk is a city in North-Eastern Belarus, the administrative center of Vitebsk region and Vitebsk district.
A population of 374 174 persons (1 October 2015)[4]. Area — 124,538 km2.
The city is located in the Eastern part of Vitebsk region on the banks of the Western Dvina river. The second most ancient city in Belarus after Polotsk. Fourth by population (after Minsk, Gomel and Mogilev) city in the country.
The town was founded on the high banks of the Western Dvina and Vitba, which gave him the name that is on the way "from the Varangians to the Greeks". As the urban legend of the 18th century it was founded by the Saint equal to the apostles Princess Olga. The city was formed as one of the centres of the Association of Slavic Krivichi, and a convenient geographical position at the crossroads of major trade routes contributed to the growth and prosperity over the next centuries
решение. 1. ri=2*r; rii=r/2; ri/rii=4; не надо ни о какой площади сечения говорить. два куска проволоки содинили последовательно, получили ri=2*r; два куска той же проволоки соединили параллельно, получили rii=r/2; ну, а теперь раздели первое на второе!
а теперь общий случай: ri=r*n; rii=r/n; ri/rii=n^2; кусок проволоки разрезали на n одинаковых кусков. сначала эти куски соединяют последовательно: ri=r*n; затем соединяют параллельно rii=r/n; ну и дели первое на второе и делай выводы.
A population of 374 174 persons (1 October 2015)[4]. Area — 124,538 km2.
The city is located in the Eastern part of Vitebsk region on the banks of the Western Dvina river. The second most ancient city in Belarus after Polotsk. Fourth by population (after Minsk, Gomel and Mogilev) city in the country.
The town was founded on the high banks of the Western Dvina and Vitba, which gave him the name that is on the way "from the Varangians to the Greeks". As the urban legend of the 18th century it was founded by the Saint equal to the apostles Princess Olga. The city was formed as one of the centres of the Association of Slavic Krivichi, and a convenient geographical position at the crossroads of major trade routes contributed to the growth and prosperity over the next centuries