12cos^2a=12*(1/(1+tg^2a))=12*(1/(1+5))=12/6=2
360 | 360 | 16 | 16 | 90 | 0.009 | 2.5 | 10 | 0
3600 | 3600 | 16 | 16 | 90 | 0.09 | 25 | 10 | 0
ах+6а+х^2-3ах=9