в каких случаях используется среднее арифмичическое​

Найти производную y '= 1 - cosx / 1+cosх

Человек находящийся в покое, за 1 минуту поглощает до 200 см^3 кислорода. Вычислите массу кислорода, поглощаемую человеком за 1ч(плотность=1?430кг\м в кубе)

помогите пожалуйста(((((

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ФРАЗЫ: 

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ТЕКСТ:

 Education Abroad
The value of a student exchange between foreign families is an experience of a lifetime. The mixing of cultures and backgrounds provides young people with an unforgettable awareness and a lifelong appreciation of each other. Everyone in the family, in fact, benefits from this new understanding and friendships start.
There is no better way to learn about another country, its customs and its people's way of life than by experiencing it firsthand as a student exchange participant. Year after year study abroad education enhances students' lives. They gain skills they could never have learnt by staying home, including maturity, self-confidence, communicativeness, and the ability to become a global citizen. To learn more about the advantages of becoming a foreign exchange student take a look at the previous topics or search directly for a specific programme in the list.

Очень НАДО пОмоГиТе ПоЖаЛуЙста((((((((((((((