Предмет: Алгебра, автор: Лолик2000

ребята, помогите, пожалуйста, с алгеброй! очень нужно

1) cos^2 a*tg^2a+sin^2a*ctg^2a
2) 1-sin^2a-cos^2 a

Ответы

Автор ответа: Freakazoid
0
1); cos^2a*tg^2a+sin^2a*ctg^2a=cos^2a*frac{sin^2a}{cos^2a}+sin^2a*frac{cos^2a}{sin^2a}=\sin^2a+cos^2a=1;\ 2); 1-sin^2a-cos^2 a=(1-sin^2a)-cos^2a=cos^2a-cos^2a=0.
Предыдущий вопрос
Следующий вопрос
Похожие вопросы
Предмет: Химия, автор: maksimsosnovskij
Вычислите массу оксида бария, образовавшегося в результате взаимодействия бария с 67 г кислорода.
7 лет назад
Предмет: Английский язык, автор: Аноним
СРОЧНО!! ДАЮ 100 БАЛОВ, СПАСИБО ЗАРАНЕЕ!!!


Read the text and do the tasks after it.

I go to school five days a week except Saturday and Sunday. Classes in our school start at 8 o'clock in the morning and last till 14.30. Usually we have 6 or 7 lessons a day. We study a lot of different subjects: Ukrainian, English, History, Geography, Biology, Physics, Math, etc. I like History, Ukrainian and English most of all. I usually get good marks for these subjects.

A school year is divided into four terms. It begins on the 1st of September known as the Day of knowledge and finishes in May. Each term is followed by holidays that last one week in autumn and spring and two weeks in winter.

Our school was built about ten years ago. Our classroom is on the third floor. Its windows face the school-yard. There are two large windows in our classroom; a great amount of flowers grow in pots that stand on the window-sills. It is pupils of our class who are responsible to water the flowers several times a week. And we all do it with great care and pleasure. On the walls of our classroom there are different colour maps and portraits, tables and wall newspapers.

Every pupil has a record book where our teachers write down our marks and we write down home tasks. Lessons usually take place in such a way that a teacher asks a question and the pupils who can give an answer raise their hands and the teacher calls out one of them to answer the question. Teachers often call pupils to the blackboard to do different exercises or to write some sentences from dictation. When they make a mistake, other pupil can be called out to correct a mistake or sometimes the teacher corrects it themselves. After every lesson teachers give us home tasks both written and oral ones.

I like going to school because here I have many friends and wise teachers who can always give a piece of advice. And I like studying as well, it brings me a lot of pleasure and I like to learn new facts about the world.

1. Find the English equivalents for the following word combinations:

a) отримувати гарні оцінки

b) вікна виходять на

c) бути відповідальним

d) записувати домашнє завдання

e) дати пораду

2. Complete the following sentence according to the text.

It is pupils of the narrator’s class who ____________________________________________.

3. Answer the following question.

How do lessons usually take place at the narrator’s school?

4. Which of the following statements was NOT mentioned in the text?

a) Mistakes can be corrected.

b) There are six floors in this school.

c) The narrator doesn’t like studying.

d) Flowers are watered several times a week.

5. Choose the true statement according to the text.

a) Teachers never call pupils to the blackboard.

b) Pupils have to do only oral tasks at home.

c) Teachers give students home tasks.

d) Teachers water all the flowers at school.
7 лет назад
Предмет: Русский язык, автор: garakirill2011
Разобрать предложение Наступила радостная шумная весна
7 лет назад
Предмет: Обществознание, автор: lonnik
(Ребят, помогите пожалуйста)Нужно
срочно эссе, на тему: "нынешняя молодеьж привыкла к роскоши, она отличается дурными манерами, презирает авторитеты, не уважает старших, дети спорят со взрослыми, жадно глотают пищу, изводят учителей"(За ранее, спасибо большое)
10 лет назад
Предмет: Математика, автор: sergs1
запиши выражения и найди их значения. разность чисел 560 и 20 уменишить в 9 раз.произведение чисел 90 и4 увеличить на 30.сумму чисел 120 и 60 уменьшить в 3 раза
10 лет назад