UR-Exercise 1. Use modal verbs or their equivalents.1. The deciduous teeth ... appear at about six months after birth.2. Teeth ... be kept clean to avoid the development of dental plaque.3. If a decayed tooth is not treated in time pulpitis ... develop.4. Although the dentist ... treat dental decay you ... give your teeth thedaily care they need.5. No dentist ... to stop a tooth if it is too bad. In this case he ... extract it.6. When a cavity is present in a tooth, the dentist will determine what ...be done to repair the damage.7. Adults ... thoroughly brush their teeth at least once a day.8. Poor mouth hygiene ... lead to infection and the development of toothdecay.9. The initial lesion of dental caries ... develop in the occlusal fissures.10. In case of caries a dentist ... first gain access to it.11. Caries removal ... start in the area of cavitation.12. Caries lesions ... occur both on pits and fissures and smooth surfaces.13. Sometimes even a dentist ... help if disease is neglected.14. The resistance of enamel to dental caries ... be increased by applicationof fluoride to the tooth surface.15. Fluoridation of water ... make teeth more resistant to caries.
Ответы
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
Ответить на вопрос
Поделитесь своими знаниями, ответьте на вопрос:
Популярные вопросы в разделе
Придумайте по 5 предложений с началом there is, there are.
Автор: n-896458
3 предложения с гл. to be и 3 во предложения с Do Does
Автор: rusmoney92
1 will
2 must
3 can
4 would must
5 can will
6 would
7 must
8 can
9 will
10 must