1)Укажите корни уравнения cos^2x-7cos2x= 8+sin^2x принадлежащие промежутку [-2pi;2pi]

2)Решить уравнение cos3x-sinx=(sqrt 3)(cosx-sin3x)

3)Решить систему неравенств
sinx<1/2
tg2x>(sqrt2) 
можно описать решение

Писала грамматику, хотелось бы знать правильные ответы! Заранее спасибо =)

1) Something ________ (go) wrong with our computer. Customers ______ (ring) up all morning complaining. The mechanic is in the office and _______(work) on it. I hope he will find out what is wrong.

2) _______ society which they set out to create was based on _______ mutual trust.

3) ________ ordinary and white chocolate are made from cocoa butter. There are very few people who like ________ of them. I have no particular preference: I eat _________.  (all, whole, either,neither, none, both)

4) Nobody knows where the jewels  have/has  gone. They _____________ (might/have to/ought to/steal)

5) The evacuation of the building/ The building's evacuation   took only 10 min.

6) All of us were lucky. We __________ (crash) if Jack _________ (not see) the rock in time.

7) What/How was the journey like? - It was nice!

8) The miners dug deep/deeply to find coat.

9) The firs draft resolution ____________ (not discuss) yesterday, it __________ (withdraw) long before the beginning of the meeting.

10) Do you know where was he born/ he was born ?

11) Get your children feel/felt/to feel responsible for their studies.

12) Her salary's decreased _____ two hundred dollars this year.

Колебательный контур создаёт в воздухе электромагнитные волны длиной 150м. Какая ёмкость включена в контур, если его индуктивность 0,25 мГн.

Активным сопротивлением пренебречь.

Решите пожалуйсто , и пожалуйсто простым решением

Выразите из формулы  [tex] t= t_{0} + \frac{s}{u}[/tex]

Переменную s

Буква А ничего не значит , я ее вообще не добовлял!