# Boldly Folding (part 1)

**Algebra**Level 3

Which function describes the new position of a point \(P = (x, y)\) on the paper after the fold?

\(f(x, y, W, L) = \left\{ \begin{array}{rl} (W-x,y) &\mbox{ if $x<\frac{W}{2}$} \\ (x, y) &\mbox{ otherwise} \end{array} \right.\)

\(f(x, y, W, L) = \left\{ \begin{array}{rl} (W^{2}-x,y+L-W) &\mbox{ if $x>\frac{W}{2}$} \\ (x, y) &\mbox{ otherwise} \end{array} \right.\)

\(f(x, y, W, L) = (W - x, L-y)\)

\(f(x, y, W, L) = (\frac{\pi x}{W}, \frac{y}{\pi L})\)

**Details and assumptions:**

- The paper has infinitesimal thickness.