докажите:

cos2a-sin(П+а)sin(4П+a)=cos*2a

4sina cosa+ sin(2a-П)=sin2a 

 

На правом или на левом берегу реки Тибр возник город Рим?

Задача:В четырёх ящиках всего 86 кг яблок:в первых двух поровну,в третьем 20кг,а в четвёртом 18кг.Сколько килограммов яблок в первом ящике?

раскрыть скобки, поставив глаголы в Past Simple. I (to be) about 2 o'clock in the morning, and... suddenly I (to wake) up. I (to hear) a noise. I(to get) out of bed and (to go) slowly downstairs. There (to be) a light on in the living room. I (to listen) carefully. I (can) hear two men speaking very quietly. "Burglars!" I (to think). "Two burglars!" immediately I (to run) back upstairs and (to phone) the police. I (to be) really frightened. Fortunately the police (to arrive) quickly. They (to open) the front door and (to go) into the living room. Then they (to come) upstairs to find me. "It's all right now, sir," they (to explain). "We (to turn) the television off for you!"

По графику y=1-x2 найти значения х при которых y принимает положительные значения,отрицательные значения