sin(arcsin3/5+arcsin8/17)=sin(arcsin3/5)cos(arcsin8/17)+cos(arcsin3/5)sin(arcsin8/17)=3/5*15/17+4/5*8/17=77/85cos〖1/2arccos(-3/5)〗=根号下[1+cosarccos(-3/5)]/2=根号下1/5