вычислите массу осадка, которая образуется из 35.5г Na2SO4 и Ba(NO3)2

1-sin(x/2 + п/3)=0; 5sin(2x-1)-2=0; cos(6+3x)=-корень2/2; (1-корень2cosx)*(1+2sin2xcos2x)=0; 6cos^2x+7cosx-3=0.

Помогите пожалуйста решить 2 уравнения:)Срочно!Решать надо только д)  е)   без проверки

напишите пожалуйста сочинение)))))))

         по плану

1 )в лес за грибами

2)змея!!!

3)страхи оказались напрасными) пожалуйста!!!!!!!!!!!!!!!))))))))))

вообщем надо написать репорт про какое либо проишествине не так давно произошедшее... Типа падения метеорита челябинск , землетрясений и т.д. 

За основу можно взять данныей текст 

I'm going to talk about a phenomenon which happens very often in spring and summer and causes a lot of damage and even the deaths of people and animals. This is flooding. We call it a flood when a very large amount of water covers an area that is usually dry.
I am going to use St Petersburg as an example of an area that gets regularly flooded. Floods in St Petersburg have a long history. Some of the floods were really disastrous. They not only destroyed buildings and streets but also killed and injured people.
When people started living on the Neva River in 1700, they didn't build houses — they just built light huts which could be easily put on rafts and tied to trees, so as not to be carried away by floods.
In 1715, there was a very big flood. If you look at the picture at the top you can see that some people used boats and others stayed on the roofs of their houses. All the city bridges and buildings on the banks of the river were destroyed by the flood. Many people drowned. Lots of cows, pigs and goats died.
The second picture illustrates the biggest flood the city has ever seen. It was in 1777 when the water was about 3.5 metres higher than its usual level. There were no streets and squares any more — just one big lake. The storm was severe. The following facts show the scale of the disaster: 2,000 trees were torn out and carried away. Just imagine a wooden house was moved to the opposite bank of the Neva River.
Since that time there have been big floods in the city every five years. So people started building firm constructions. They also decided to build a dam to protect the city from flooding.
To conclude I'd like to say that though floods can be severe and dangerous, people can learn how to tame them and survive.

(размер репорта от полутара страниц тетрадного листа) Зарание спасибо