0+1+z`_(y)=(-sin(x-z))*((x-z))`_(y)
1+z`_(y)=(-sin(x-z))*(0-z`_(y))
z`_(y)(sin(x-z)-1)=1
[m]z`_(y)=\frac{1}{sin(x-z)}
[m]z``_(yy)=-\frac{1}{sin^2(x-z)}\cdot (x-z)`_{y}[/m]
[m]z``_(yy)=-\frac{1}{sin^2(x-z)}\cdot (-z)`_{y}[/m]
[m]z``_(yy)=\frac{1}{sin^2(x-z)}\cdot z`_{y}[/m]
[m]z``_(yy)=\frac{1}{sin^2(x-z)}\cdot\frac{1}{sin(x-z)}[/m]
[m]z``_(yy)=\frac{1}{sin^3(x-z)}[/m]