熱心網(wǎng)友
arccos(-a)=π-arccos(a) ①arccos(-a)=arccos(a) ②由①②知π-arccos(a) =arccos(a)即 arccos(a)=π/2 a=cos(π/2) a=0當(dāng)a=0時(shí),arccos(-a)=arccos(a)
arccos(-a)=π-arccos(a) ①arccos(-a)=arccos(a) ②由①②知π-arccos(a) =arccos(a)即 arccos(a)=π/2 a=cos(π/2) a=0當(dāng)a=0時(shí),arccos(-a)=arccos(a)