Народ, сделать все. отмечу лучшим! докажите тождество: а) б) в)

Решение по

А)2sinπ/6cosa+2cosπ/6sina-√3sina=2*1/2sina+2*√3/2sina-√3sina=sina+√3sina-√3sina= =sina б)(sinacosb+cosasinb)(sinacosb-cosasinb)+sin²b=sin²acos²b-cos²asin²b+sin²b= =sin²acos²b+sin²b(-cos²a+1)=sin²acos²b+sin²bsin²a=sin²a(cos²b+sin²b)=sin²a в)(sinacosb+cosasinb-2sinacosb)/(2cosacosb-cosacosb+sinbsina)= =(cosasinb-sinacosb)/(cosacosb+sinbsina)=sin(b-a)/cos(b-a)=tg(b-a)

1.Составить во к следующим ответам.

     1. I am doing my homework now.

     2. They usually  do their homework in the evening

     3. My mother went shopping last Friday.

     4. My friends have been in Italy 2 years ago.

2. Используйте глаголы в скобках в правильной форме.

     1. I _______________(has written, wrote, have written)

the letter yesterday.

     2. Tamara ___________ (has, have) already _________ (cleans, cleaned) the room.

     3. I __________ (have done, is doing, am doing) my lessons now.

     4. He ______________ (has done, have done, did) his exercises till six o’clock.

Объяснение:

1.Составить во к следующим ответам.

     1. I am doing my homework now.

     2. They usually  do their homework in the evening

     3. My mother went shopping last Friday.

     4. My friends have been in Italy 2 years ago.

2. Используйте глаголы в скобках в правильной форме.

     1. I _______________(has written, wrote, have written)

the letter yesterday.

     2. Tamara ___________ (has, have) already _________ (cleans, cleaned) the room.

     3. I __________ (have done, is doing, am doing) my lessons now.

     4. He ______________ (has done, have done, did) his exercises till six o’clock.

1.Составить во к следующим ответам.

     1. I am doing my homework now.

     2. They usually  do their homework in the evening

     3. My mother went shopping last Friday.

     4. My friends have been in Italy 2 years ago.

2. Используйте глаголы в скобках в правильной форме.

     1. I _______________(has written, wrote, have written)

the letter yesterday.

     2. Tamara ___________ (has, have) already _________ (cleans, cleaned) the room.

     3. I __________ (have done, is doing, am doing) my lessons now.

     4. He ______________ (has done, have done, did) his exercises till six o’clock.

Объяснение:

1.Составить во к следующим ответам.

     1. I am doing my homework now.

     2. They usually  do their homework in the evening

     3. My mother went shopping last Friday.

     4. My friends have been in Italy 2 years ago.

2. Используйте глаголы в скобках в правильной форме.

     1. I _______________(has written, wrote, have written)

the letter yesterday.

     2. Tamara ___________ (has, have) already _________ (cleans, cleaned) the room.

     3. I __________ (have done, is doing, am doing) my lessons now.

     4. He ______________ (has done, have done, did) his exercises till six o’clock.