Предмет: Алгебра, автор: Лекпар

Найдите cos альфа, если sin альфа = - корень 3 /2 и альфа принадлежит (пи; 1,5 пи)

Ответы

Автор ответа: Yena

0

так как α в третьей четверти то cosα<0

$cosalpha=-sqrt{1-sin^2alpha}$

$cosalpha=-sqrt{1-frac{3}{4}}=-sqrt{frac{1}{4}}=-frac{1}{2}$

Предыдущий вопрос

Следующий вопрос

Интересные вопросы

Предмет: Английский язык, автор: alibekzhuldyz0885

Reading B. Read the essay and answer the questions. Pets: Having a pet can be fun and enjoyable. But is keeping pets a good or bad thing? Pets can be good company for people who live alone and for children. Children always enjoy having a cat or dog to play with. What is more, having a dog around the house makes people feel safe. Aiso, children learn to become more responsible by taking care of a pet. On the need care and attention every day and they may feel hours or travel a lot the other hand, it is not always easy to have a pet. Many people get a pet without realising money and time they have to spend in order to keep it happy and healthy. Moreover, pets lonely when their owners work long All in all, having a pet is a great experience. However, people should they have the time to take proper care of their pet before they get one. 1 Who are pets good company for? 2 How can having a pet help children? 3 What do pets need from their owners on a daily basis? 4 What problem do pets whose owners are often away from home have? 5 What should people think about before getting a pet? Writing D. Write a short description of your favourite hobby (80-100 words). Use the description in Ex. H and the plan below to help you. • Paragraph 1: What is your favourite hobby and why. Paragraph 2: • Paragraph 3: When/Where do you do it, what equipment do you need, etc. Conclusion and recommendation, be absolutely sure that Good or Bad? Marks: Marks 10

7 лет назад

Предмет: Математика, автор: tleugazyalmas

. Во сколько раз увеличится периметр квадрата, если его площадь увеличилась в 100 раз?

7 лет назад

Предмет: Русский язык, автор: bypada

с р о ч н о ! п о ж а л у й с т а п о м о г и т е !

7 лет назад

Предмет: Математика, автор: loj22

Поставь скобки, чтобы равенства стали верными: 1000-990:10-1=902; 960:2+6=120

10 лет назад

Предмет: Алгебра, автор: маринка8

какая из точек А(-1;1); В(0;-2), С(0;2), В(1;3) принадлежит графику линейного уравнения 2x - 3у + 7 = 0

10 лет назад