1.原式=2*(1/2*sin105-3^(1/2)/2*cos105)=2*(cos60*sin105-sin60*cos105)=2*(sin(105-60))=2^(1/2)2.原式=2*(3^(1/2)/2*cos15-1/2*sin15)=2*(cos30*cos15-sin30*sin15)=2*(cos(30+15))=2^(1/2)其中2^(1/2)表示根号2...