注意 y=arcsinx 是 y = sinx ,x∈[-π/2,π/2] 的反函數(shù).
對該題,y = sinx = - sin(x+π),y∈[0,1]
即 -y = sin(x+π),x+π∈[-π/2,0]
從而 ：x+π = arcsin(-y) = - arcsiny ,
得到反函數(shù)為：y = - arcsinx - π,x∈[0,1].