Допиши рівняння реакції. Розстав коефіцієнти : ( )Br₂+( )( ) = ( )AlBr₃
а)2Br₂+3Al = 3AlBr₃
б)3Br₂+Al = AlBr₃
в)3Br₂+2Al = AlBr₃
г)3Br₂+2Al = 2AlBr₃

Sara( 1. go) through to the study and (2.pick) up the receiver. -Hello, Sara. This is Perry. I (3. speak) from the airport. I (4. fly) to New York in half an hour. I (5. be) there at about three. Can we meet for dinner? - Perry I of course, - she (6. stammer) taken totally by surprise. - I (7. ring) you again, when I (8. arrive). Sare (9. return) to the hall to say good-bye to her sisters-in-law. They (10. leave) to catch their flights. When they (11. go) the house (12. seem) very quiet.

They shared the car to the city. " We(1. go) the theatre after dinner," Mrs. Elliot said. " I (2. look) forward to it. I (3. not\ be) to the theatre for this weeks. There (4. be) such an exciting atmosphere in the theatre, don't agree? You (5. visit) the theatre often in London, dear"? " Quite often", Sara agreed. "I (6. enjoy) it, too," " Is this friend of yours a close friend?" Mrs. Elliot asked. Sara hesitated. "I (7. see) quite a lot af him lately, she admirtted. The cas (8. stop) at the hotel and Sara (9. go) out. Perry ( 10.wait) for her in the entrence hall. She (11.decide) to tell him everything after they (12. eat)

дано: sin a = -0.6;       П < a < 3П/2 

Найти:

а) cos a; 

б) tg a;

в) ctg a;

г) cos (П/3 - а)