Solve y=operatorname{Arccos}x/a

$$y = \operatorname { Arccos } \frac { x } { a }$$

Solve for a

$$\left\{\begin{matrix}a=\frac{x}{\cos(y)}\text{, }&y\leq \pi \text{ and }y\geq 0\text{ and }\left(\exists n_{2}\in \mathrm{Z}\text{ : }\left(y>\pi n_{2}+\frac{\pi }{2}\text{ and }y<\pi n_{2}+\frac{3\pi }{2}\right)\text{ or }y\neq \frac{\pi }{2}\right)\text{ and }x\neq 0\\a\neq 0\text{, }&\exists n_{1}\in \mathrm{Z}\text{ : }y=\pi n_{1}+\frac{\pi }{2}\text{, }n_{1}=0\text{ and }x=0\end{matrix}\right.$$

Solve for x

$$x=a\cos(y)$$

$$y\geq 0\text{ and }y\leq \pi \text{ and }a\neq 0$$