1、sin750° =sin(720 °+30 °)=sin30°=1/22、cos 22π/3 =cos(8π-2π/3)=cos2π/3=-1/23、tan(-7Π/4)=tan(-2π+π/4)=tanπ/4=14、 sin900°=sin(720 °+180 °)=sin180 °=0