Предмет: Алгебра, автор: nemova1995

1. Cos(2arccos4/5)
2.cos(pi-2arccos4/5)

Ответы

Автор ответа: dasdasfa
0
1) =2*cos(arccos(4/5))-1=2*(4/5)^2-1=32/25-1=7/25  (по формуле cos^2 x=(1+cos2x)/2
2) =-cos 2arccos(4/5)=-7/25
Автор ответа: mmb1
0
1. Cos(2arccos4/5)=2cos²(arrcos4/5)-1=2*4/5*4/5-1=32/25-1=7/25
2.cos(pi-2arccos4/5)=-cos(2arccos4/5)=-7/25
Предыдущий вопрос
Следующий вопрос
Похожие вопросы
Предмет: Английский язык, автор: 30072008vika
Допоможіть будь ласка. Треба дати відповідь по тексту. Miklukho-Maclay was a Ukrainian scientist and traveller who lived more than a year on the island of New Guinea. The ship came to the island in the evening of a day in September 1871. Next morning the captain said to Maclay:
“You are coming ashore. Why don’t you take more men with you? Have you a gun?”
“I don’t need a gun. I have presents for the natives.”
The island was beautiful. There were trees and flowers everywhere, and it was very hot. The sun was shining brightly high above Maclay’s head. He walked for some time down a forest path. Suddenly he stopped because he heard a noise. A native stood in front of him. He looked at Maclay quickly and then started running away. Maclay ran after him. The native looked back and suddenly stopped. Maclay took out some presents and showed them to the man. The native took the presents and smiled. This was how Miklukho-Maclay met the first black man on the first day of his life in New Guinea. The native’s name was Tui. He was Maclay’s best friend all the time that the traveller lived on the island.
On the first of October Maclay started out for a walk in the forest. He carried no gun. He had only a notebook and a pencil. In the forest, he met a native boy who saw him and ran away. Maclay heard the voices of men and women and the cries of children. Suddenly many men with spears in their hands came out. They stopped and looked at Maclay angrily. When he tried to say something, one of the men wanted to throw his spear at him. Maclay did not know a word of their language. He could not explain that he was their friend. He knew that he had to do something quickly. And a good idea came to him. He suddenly sat down on the ground and began to take off his shoes. Then he lay down, put a bag under his head and … slept. The natives did nothing to him.
Variant 1
Task 1. Define whether the statements are true or false.
1. Miklucho-Maclay lived in New Guinea for more than two years.
2. The island was beautiful.
3. Tui ran away from Maclay.
4. The natives didn't like Maclay's presents.
5. Maclay had only a notebook and a pen when he walked in the forest.
6. A man wanted to kill Maclay.
Task 2. Answer the questions.
1. What was Maсlay's profession?
2. What did he take to New Guinea for natives?
3. How did the natives meet Maclay?
4. Why didn't Maclay explain the natives that he was a friend?
5. What did Maclay decide to do to save his life?
6. Did the natives understand Maclay?
7 лет назад
Предмет: Қазақ тiлi, автор: erkenur07
Достық туралы ұлы тұлғалардың пікірлері керек?!
7 лет назад
Предмет: Геометрия, автор: romagunek272005
Побудувати паралельну прекцію прямокутної трапеції АВСD, у якій АD перпендикулярна АВ, АВ : DС = 2 : 1
7 лет назад
Предмет: Математика, автор: marsianin2

из 6 одинаковых кубиков с ребром 3 см сложили парралепипед  короче там надо узнать площадь закрашенного там его короче закрасили парралепипед и вот узнать пложадь по ребрам
10 лет назад
Предмет: Математика, автор: Leras20021

Решите задачу без составления уравнения: В трамвае ехало несколько пассажиров. На первой остановке вышло 6 и вошло 8 пассажиров, на второй остановке вышло 13 и вошло 2 пассажира. После чего в трамвае стало 35 пассажиров. Сколько их было до первой остановки? Напишите по действиям пожалуйста!
10 лет назад