Чему равно тождество (sina+cosa)^2 - №12535490

Чему равно тождество (sina+cosa)^2
- Предмет:
  Алгебра
- Автор:
  valentinawalsh
- 5 лет назад

Ответы 1

$=sin^{2}a+2sinacosa+ cos^{2}a=1+2sinacosa=1+sin2a$
- Автор:
  mirandameyer
- 5 лет назад
- 0
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True,False or Not Stated
Halloween

Halloween dates back to an ancient Celtic festival. The Celts, who lived 2,000 years ago in the area of Ireland, the United Kingdom and northern France, celebrated their new year on November 1. This day showed that the summer was over and winter had come. Because of the cold and darkness, winter was associated with human death.

Celts believed that on Halloween night the ghosts of the dead returned to earth. With their help, the Druids or Celtic priests, could predict the future. It was important because people depended on the natural world which was dangerous and changeable. They wanted to know what their life would be like in the next year.

For this event the Druids built big bonfires, where the people gathered to burn crops and animals. It was a gift to the Celtic gods. During the celebration, the Celts wore costumes made of animal heads and skins. They sang, danced and listened to the stories the Druids told them. When the celebration was over, they went home and brought burning pieces of wood with them. They lit their fires and hoped it would ensure good fortune and protect the family during the winter.

The first celebrations of Halloween in America were public events. Neighbours got together to celebrate the harvest and tell each other stories of the dead. They also sang and danced. By the middle of the nineteenth century, these autumn festivals were common, but Halloween was not yet celebrated everywhere in the country.

In the second half of the nineteenth century, lots of immigrants started coming to America. They helped to make the celebration of Halloween a popular national event. Americans began to dress up in frightening costumes and go from house to house asking for food or money. The most popular characters were witches, ghosts, and vampires. Everyone tried to look as ugly and scary as possible.

Halloween is closely associated with the Jack-o’-lantern, a pumpkin with a candle inside that shines through the holes to make a horrible face. Most people think that the Jack-o’-lantern is an American tradition. However, the original Jack-o’-lantern was not a pumpkin but a man who, according to the old Irish legend played a trick on the devil himself. He was punished for that and was accepted neither to heaven nor to hell. The Irish people shared the legend with the Americans and showed them how to make Jack-o’-lantern out of the pumpkin.

By the 1930s, Halloween had been celebrated with parades, town-wide parties and lots of other entertainment. Later a new tendency appeared. By the 1950s, Halloween had changed into a holiday directed mainly at children. On that evening children in costumes travel from house to house in order to ask for treats (such as some sweets, a small present or a few coins) with the question “Trick or treat?” The trick is a threat (usually not working) to perform mischief on the owner of the house if no treat is given. “Trick or treat?” has become a traditional practice on Halloween in many countries.

1)Halloween came to the USA only in the 20th century.
1)True 2) False 3)Not Stated
2) “Trick or treat” means “we wish you good luck”.
1)True 2) False 3)Not Stated
3) The Irish immigrants taught Americans how to use pumpkins for Halloween ceremonies.
1)True 2) False 3)Not Stated
4)From the middle of the 20th century, children have taken an active part in Halloween celebrations.
1)True 2) False 3)Not Stated
5)In ancient times fires were prohibited on Halloween night.
1)True 2) False 3)Not Stated
6)The Celts paid the priests for their predictions
1)True 2) False 3)Not Stated
7)The church strongly disapproved of Halloween celebration in America.
1)True 2) False 3)Not Stated
8) For the Celts Halloween was associated with the change of the seasons.
1)True 2) False 3)Not Stated
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y eqv (((x and y) or y)xor (x imp (x xor y)))
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vbs
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