sin(-1470度)cos1740度+cos(-660度)sin750度tan405度qiuzhi 求值

sin(-1470度)cos1740度+cos(-660度)sin750度tan405度
=sin(-1440°-30°)cos(1440°+30°)+cos(-720°+60°)sin(720°+30°)tan(360°+45°)
=-sin30°cos30°+cos60°sin30°tan45°
=-√3/4+1/4
=(1-√3)/4

sin(-1470度)cos1740度+cos(-660度)sin750度tan405=sin(-1440-30)cos(1800-60)+cos(-720+60)sin(720+30)tan(360+45)=sin(-30)cos60+cos60sin30tan45=-1/2*1/2+1/2*1/2*1=0