Моток медной проволоки сечением 2 кв. мм имеет массу 17,8 кг. Как, не разматывая моток, определить длину проволоки? Чему она равна?

С аэродрома одновременно поднялись в воздух два самолёта и полетели в противоположны направлениях. Скорость каждого самолёта 850 км/час. на каком расстоянии будут самолёты один от другого через 3 часа полёта? ( напишите схемой)

          ПЕРЕВЕДИТЕ БЕЗ ПЕРЕВОДЧИКА.

     "But the star didn't come off.Then the king took the biggest book but it said nothing about cows with stars on their horns.Except the story of the Cow Who Jumped Over the Moon.

   "Try that too" the king said.

   "Try what ?" said the red cow.

    " Try to jump over the Moon. I think it will help."

     "Me?" the red cow was very surprised. " I'm a serious animal. Jumping is not good for a lady."

    "Madam , " the king said , " do you want to go on a dancing ?Do you like to feel  hungry and sleeepy ?"

    " The red cow thought of the sweet yellow flowers and soft grass. And she said , " I'll try it ".

    " And they went to the garden.

   " Now," said the king. " One!Two!Tree!"

   " That moment the red cow jumped and flew up into the sky. She looked down. The king growing smaller and smaller.She wen higher and higher thriught the dark sky. The stars were dancing around her like great golden plates. Then she closed her eyes because the moonlight was very bright and cold. Suddenly the star fell of with a great noise.

 " Next moment the red cow came down on the Earth again. To her great surprise she was in her  green field. And she stopped dancing !

Алгебраические выражения.Алгебраическая сумма.Значение алгебраического выражения.

Найдите значение выражения

1. 2)7-2b при b=-1,3;

    4)4+5d при d=-3,6;

2. 2)c-4d при c=-5, d=0,25

    4)2m-3n при m=-1,5 n=1\6

3. 2)cd+9 при c=0,3 d=-5

    4)xy\4 при x=8 y=-0,5

Решите пожалуйста уравнение tg2x=√3/3 Если можно поподробнее...:)