Sin(arcsin(12/13)+arccos(15/17))

sin(arcsin12/13+arccos15/17)=sin(arcsin12/13)cos(arccos15/17)+cos(arcsin12/13)*sin(arccos15/17)=12/13*15/17+(√1-(12/13)²)*(√1-(15/17)²)=180/221+5/13*8/17=(180+40)/221=220/221