Ответы на вопрос:
1) sin120 = sin(90 + 30) = sin90cos30 + cos90sin30 = 1*√3/2 + 0*1/2 = √3/2
2) cos210 = cos(180 + 30) = cos180cos30 – sin180sin30 = (-1)* √3/2 – 0*1/2 = -√3/2
3) sin20cos25 + cos20sin25 = sin(20 + 25) = sin45 = √2/2
1)sin120=sin(180-60)=sin60=√3/2 2)cos210=cos(180+30)=-cos30=-√3/2 3) sin 20 * cos 25 + sin 25 * cos 20=sin(20+25)=sin45=√2/2
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