2sin(-420)=-2sin(180+240)=-2(sin180cos240+sin240cos180)=-2sqr(2)/2=-sqr2
2cos60-tgп/4=2*1/2-1=1-1=0 c0s60=1/2 tgп/4=1
2sin(-420)=-2sin(180+240)=-2(sin180cos240+sin240cos180)=-2sqr(2)/2=-sqr2
2cos60-tgп/4=2*1/2-1=1-1=0 c0s60=1/2 tgп/4=1