sinA=根号下6 /4=0.61237243569579452454932101867647
A=arcsin0.61237243569579452454932101867647
=37.761243907035038060614482600436度
sinA=根号下6 /4=0.61237243569579452454932101867647
A=arcsin0.61237243569579452454932101867647
=37.761243907035038060614482600436度