Question

Помогите вычислить:
cos510° - sin1200° - tg1005°

Answer 1

510=360+180-30
cos(510)=-cos30
sin1200=sin120=sin(90+30)=cos30
cos510-sin1200-tg1005=-cos30-cos30-tg(90+15)=-sqrt(3)+ctg15
ctg15=sin30/(1-cos30)=1/(2-sqrt(3))
1/(2-sqrt(3))-sqrt(3)=2+sqrt(3)-sqrt(3)=2