<li> <kbd>s, t, u, v, n, i, j, w, h, z, r, g, b, a, o, c, y, m, k</kbd>: symbols</li>
<li> <kbd>abs(</kbd><em>x</em><kbd>)</kbd>: absolute value function</li>
<li> <kbd>acos(</kbd><em>x</em><kbd>)</kbd>: arc cosine function</li>
<li> <kbd>s, t, u, v, n, i, j, w, h, z, r, g, b, a, o, c, y, m, k</kbd>: symbols</li>
<li> <kbd>abs(</kbd><em>x</em><kbd>)</kbd>: absolute value function</li>
<li> <kbd>acos(</kbd><em>x</em><kbd>)</kbd>: arc cosine function</li>