Ответы и объяснения

2013-03-20T14:20:00+04:00

5. cos(П/5+2П/15)= cos П/3= 1/2

6.sin( 3П/8-5П/24)= sin 4П/24= sin П/6= 1/2

8. tg(13+32)= tg 45=1

9.tg(65-35)= tg 30=√3/3

10. tg (111+24)= tg 135= -1

11. tg( 67+83)= tg 150= √3/3

12. sin (7+47)/sin (13+41)= sin 54/sin54=sin1=П/2

13. cos (51+12)/ sin (13+14)= cos 63/sin27= сtg 7/3

14. (cos(105-75)-cos(105+75))/2= (cos30-cos180)/2= ((√3/2)+1)/2

15.(sin(П/24+7П/24)+sin(7П/24-П/24))/2= (sin 8П/24+sin(6П/24))/2= (sinП/3+sin П/4)/2= ((√3/2)+(√2/2))/2

16. (cos240 + cos30)/2= (-1/2+ 1/2)/2=0

17.2 cos 60*cos 45= 2* (√3/2) * (√2/2)