=sin(arcsin12/13)*cos(arccos15/17)-cos(arcsin12/13)*sin(arccos15/17)=12/13*15/17- -√(1-(12/13)^2))*(√(1-(15/17)^2)=(12*15)/(13*17)-√(1-144/169)*√(1-225/289)= =180/221-√25/169*√64/289=180/221-5/13*8/17=180/221-40/221=140/221
Огромное спасибо