1. The problem asks to express the answer as coordinates in terms of $z$. 2. Typically, coordinates in terms of a variable $z$ can be written as $(x, y, z)$ where $x$ and $y$ are expressed as functions of $z$. 3. Without additional context or equations, the general form is $(x(z), y(z), z)$. 4. If you provide specific equations or relations, I can solve for $x$ and $y$ in terms of $z$. 5. Please provide more details or equations to proceed with a specific solution.