sin(A-B)=SinAcosB-CosAsinB,
sinA=根号5/5,
cosA=2根号5/5,
sinB=根号10/10,
CosB=3根号10/10,
这样代入上面的公式,
sin(A-B)=根号2/10,A-B=arcsin根号2/10
sin(A-B)=SinAcosB-CosAsinB,
sinA=根号5/5,
cosA=2根号5/5,
sinB=根号10/10,
CosB=3根号10/10,
这样代入上面的公式,
sin(A-B)=根号2/10,A-B=arcsin根号2/10