Поставьте следующие предложения в отрицательную и вопросительную формы. 1. the sun rises in the east. 2. we like to do our homework together. 3. jane is cleaning the blackboard.

1) Does the sun rise in the East?
    The sun doesn't rise in the East.
2) Do we like to do our homework together?
    We do not like to do our homework together. 
3) Is Jane cleaning the blackboard?
    Jane is not cleaning the blackboard.

Сначала формулы . затем формулы двойного угла sin2α=2sinαcosα cos2α=cos²α-sin²α=cos²α-(1-cos²α)=2cos²α-1⇒  2cos²α=1+cos2α cos2α=cos²α-sin²α=1-sin²α-sin²α=1-2sin²α⇒  2sin²α=1-cos2α а) сos75°cos105°=cos(90°-15°)·cos(90°+15°)== sin15°(-sin15°)=-sin²15°=-(1-cos30°)/2=(cos30°-1)/2= ((√3/2)-1)/2=0,25√3-0,5б) sin75°sin15°=°sin(90°-15°)sin15°=cos15° sin15°=sin30°/2=1/4=0,25в) sin105°cos15°=sin(180°-75°)cos15°=sin75°cos15°=sin(90°-15°)cos15°=cos15°cos15°=(1+cos30°)/2=(1+(√3/2))/2=0,5 +0,25√3 2 способ формулы cosα·cosβ=0,5cos(α-β)+0,5cos(α+β) sinα·sinβ=0,5cos(α-β)-0,5cos(α+β) sinα·cosβ=0,5sin(α+β)+0,5sin(α-β) а) сos75°cos105°=0,5cos(75°-105°)+0,5cos(75°+105°)=0,5cos(-30°)+0,5 cos180°==0,5· √3/2+0,5·(-1)=0,25√3-0,5б) sin75°sin15°=0,5cos(75°-15°)-0,5cos(75°+15° )=0,5cos60°-0,5 cos90°=0,5·0,5=0,25в) sin105°cos15°=0,5sin(105°+15°)+0,5sin(105°-15°)= =0,5sin120°+0,5sin90°==0,5 sin(180°-60°)+0,5·1=0,5 sin 60°+0,5=0,25√3+0,5

Hello - hello  -what are you doing this weekend?   - nothing  - come with me to the computer club  - what is a "computer club"?   - if you love to play computer games, but you do not have a computer, you can play in a computer club.  - wow, this charge? - yes, but it does not require a lot of money  - good. what do i need to bring?   - if you learn well, then you can take the diary. for good learning are free to play   - can i call someone else?   - yes, of course   - i'll see you on saturday?   - well, goodbye  - goodbye