Помогите пожалуйста;) Доказать тождество cos(a+b)-cos(a-b)=-2sinasinb - №19060308

Помогите пожалуйста;)
Доказать тождество
cos(a+b)-cos(a-b)=-2sinasinb
- Предмет:
  Алгебра
- Автор:
  sammyu8ea
- 6 лет назад

Ответы 1

cosacosb-sinasinb-cosacosb+sinasinb=-2sinasinb
- Автор:
  mitzyh9ux
- 6 лет назад
- 0
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When you leave school you understand that the time to choose your future profession has come. It's not an easy task to make the right choice of a job. I have known for a long time that leaving school is the beginning of my independent life, the beginning of a far more serious examination of my abilities and character.
I have asked myself a lot of times: "What do I want to be when I leave school?" A few years ago it was difficult for me to give a definite answer. As the years passed I changed my mind a lot of times about which science or field of industry to specialize in. It was difficult to make up my mind and choose one of the hundreds of jobs to which I might be better suited.
A couple of years ago I wanted to become a doctor. I thought it was a very noble profession. I was good at biology and chemistry in the 8th and 9"1 forms. I wanted to help people who had problems with health. I knew that a doctor should be noble in work and life, kind and attentive to people, responsible and reasonable, honest and prudent. A doctor, who is selfish, dishonest, can't be good at his profession. I tried to do my best to develop good traits in myself.
Now I have already decided what to do. I'd like to be a teacher. I know that it's very difficult to become a good teacher. You should know perfectly the subject you teach, you must be well-educated and well-informed. An ignorant teacher teaches ignorance, a fearful teacher teaches fear, a bored teacher teaches boredom. But a good teacher develops in his pupils the burning desire to knowledge. As John Steinbeck once said, a great teacher is a great artist and you know how few great artists there are in the world. Teaching might even be the greatest of the arts. It's a great responsibility to bring up children. I think that's the reason why teachers are deeply respected.
More and more people realise that every educated person should know a foreign language. That's why I'm going to become an English teacher. I always remember these famous words and I'm going to teach them to my pupils: "He, who doesn't know a foreign language, doesn't know his own language".

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1. Have you made up your mind what to be in the future?
2. When did you begin making plans for the future?
3. When were you able to give a definite answer about your future profession? Did anybody help you to make the choice?
4. Are you going to work and study at the same time?
5. Why do you think teaching is a noble profession?
6. What traits must a good teacher have?
7. What difficulties of teaching profession can you name?
8. What did Steinbeck say about teaching profession ?
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как написать не употребляя букв а ю е ё следующие слова ярмо слеза сюда заяц ель ёлка
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