Ответ по предмету Алгебра: Z= 2xy- 4x-2y нужно найти экстремум функции (минимум и максимум)

Предмет: Английский язык, автор: porfinenko2015

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The beginning of railway construction in Russia may be traced as far back as the second half of the
XVIII century. Road building became closely connected with the development of the mining industry.
Among the numerous works built in the Urals the most important and the best equipped ones were
Voskresensk works. It was at those works that the first tramways in Russia were laid down to link the
mines and the works.
K.D. Frolov, a trained foreman was engaged in the construction of the tracks, and great ability and
zeal were displayed by him in that work. Later on, in 1769, K.D. Frolov succeeded in mechanizing
transportations within the shops of the works.
The next very important step was taken by A.S. Yartsev, manager of the Alexander Gun works in
Petrozavodsk, who suggested that cast iron rails should be used instead of trains, accordingly in 1788 a
railway 173,5 meters long was constructed to meet the needs of the works.
Another line with cast iron rails was constructed in the Altai Mountains by engineer R.K. Frolov, son
of K.D. Frolov, in 1809. Its length was 1867 kms. Its technical equipment was much superior to the
equipment of all the railways built in the Urals at that time. The rails R.K. Frolov used were elliptical
instead of being angular. It was on that railway that the graphic method of timing train movements was
first applied and it was R.K. Frolov who did it.
The stationary steam engine invented by I.I. Polsunov in the 1763 and installed at some plants paved
the way for the introduction of steam as tractive power on railways. The first steam loco in Russia was
constructed by the Cherepanovs, farther and son, who were considered to be the most skilled and
talented workmen of their time. In Russia many people had doubts about the possibility of using steam
engines in the Russian winter. The first railway using steam traction was put into operation at the Nizhni
Tagil metallurgical works. It was a short distance line covering only 854 metres.
Some four years later, in 1838, the inauguration of the St. Petersburg Tsarskoye Selo railway took
place. That very important railway line, which was 27 km, was soon followed in 1851, by the
construction of the Warsaw – Austrian Border railway and later on by the building of the St. Petersburg
– Moscow line 644 km in length. That was a first class double – track railway line, which linked two large
industrial and cultural centers – Moscow and St. Petersburg; 185 bridges and 19 viaducts were erected
to make the line as straight and level as possible. P.P. Melnicov and N.O. Kraft, prominent engineers,
were in charge of the construction work.

2 года назад

Предмет: Английский язык, автор: Khelot

Заполните пропуски глаголом «to be» в правильной форме. Проверьте по грамматическим таблицам,
почему были употреблены эти формы.
Hello, friend,
My name _____ James. I _____your new penfriend. I ____from the UK. I _____from London. It ___ a very interesting
city.
I ___ programmer. I work for a big company called DDC.
I ___ interested in science and business but I ____ot keen on art and politics.
I ____ also keen on traveling. My favorite country i____Spain.
My favorite writer i___Den Brown. My favorite composer i___Mozart.
My favorite music i___rock. My favorite rock star ___ Freddy Mercury.
What ___your name? How old ___ you? Where a___you from? What ___ your favorite city? Who __ your favorite
writer? Who ____ your favorite composer?
Write soon,
James

2 года назад

Предмет: Русский язык, автор: амира4

прочитай текст.Найди и запиши слова с приставками .Обозначь приставки .На верхушке берёзы сидела сойка.Затем она опустилась на нижние ветки ,несколько раз прокричала громким голосом .Услышав тревожный крик,птицы разлетелись в разные стороны.Сойка подлетела к кормушке,аппетитно поела .Ещё с собой конкурс прихватила и на старой сосне в мелкое дупло припрятала.

2 года назад

Предмет: Математика, автор: 228KUROPATOCHKA228

ПОМОГИТЕ ПОЖАЛУЙСТА!!!

там где написано (ГА) можно не делать

9 лет назад

Предмет: Окружающий мир, автор: kirinadarya81

БЫСТРЕЕ РЕШАЙТЕ! 21 ноября отмечается Всемирный день телевидения. какую роль телевидение играет в жизни современного человека? Расскажи о своей любимой телепередаче. (и нормально пишите, а то почитала, фигня всякая, ответ отстой, даю 20 баллов за хороший ответ)

9 лет назад

Z= 2xy- 4x-2y нужно найти экстремум функции (минимум и максимум)

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