For every natural integer $p \geqslant 1$ and every real number $x$, we set $\widetilde { A } _ { p } ( x ) = A _ { p } \left( \frac { x } { 2 \pi } - \left[ \frac { x } { 2 \pi } \right] \right)$. Using question III.B.1, determine the Fourier coefficients of $\widetilde { A } _ { p }$:
$$\widehat { A } _ { p } ( n ) = \frac { 1 } { 2 \pi } \int _ { 0 } ^ { 2 \pi } \widetilde { A } _ { p } ( t ) e ^ { - i n x } d x$$