## Precalculus (6th Edition)

$0^\circ+n\times 360^\circ$
In order to find the coterminal angles of a quadrantal angle, we have to add or subtract $360^\circ$. The expression that generates all coterminal angles is: $0^\circ+n\times 360^\circ$, as $n$ can be any integer, we can add or subtract any multiple of $360^\circ$.