        <b>C4_ACOSH</b> evaluates the inverse hyperbolic cosine of a C4 argument.
        </li>
        <li>
          <b>C4_ARGUMENT</b> returns the argument of a C4.
        </li>
        <li>
          <b>C4_ASIN</b> evaluates the inverse sine of a C4 argument.
        </li>
        <li>
          <b>C4_ASINH</b> evaluates the inverse hyperbolic sine of a C4 argument.
        </li>
        <li>
          <b>C4_ATAN</b> evaluates the inverse tangent of a C4 argument.
        </li>
        <li>
          <