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

докажите:

cos2a-sin(П+а)sin(4П+a)=cos*2a

4sina cosa+ sin(2a-П)=sin2a 

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!"

Эпитеты из стихотворения Тютчева "Чародейкою весною"