Вычислите 2sin750°-sin1230°+ctg1395°

Question

Вычислите 2sin750°-sin1230°+ctg1395°

Answer 1

750=2·360+30
1230=3·360+90+60
1395=3·360+270+45
2sin30-sin(90+60)+ctg(270+45)=2·1/2-cos60-tg45=1-1/2-1= -1/2