`eval', `deval'
---------------

eval(OBJ[,PREC])

deval(OBJ)
     :: Evaluate OBJ numerically.

RETURN
     number or expression

OBJ
     general expression

PREC
     integer

   * Evaluates the value of the functions contained in OBJ as far as
     possible.

   * `deval' returns double float. Rational numbers remain unchanged in
     results from `eval'.

   * In `eval' the computation is done by PARI. (*Note pari::.) In
     `deval' the computation is done by the C math library.

   * `deval' cannot handle complex numbers.

   * When PREC is specified, computation will be performed with a
     precision of about PREC-digits.  If PREC is not specified,
     computation is performed with the precision set currently. (*Note
     setprec::.)

   * Currently available numerical functions are listed below.  Note
     they are only a small part of whole PARI functions.

          `sin', `cos', `tan',

          `asin', `acos', `atan',

          `sinh', `cosh', `tanh', `asinh', `acosh', `atanh',

          `exp', `log', `pow(a,b) (a^b)'

   * Symbols for special values are as the followings. Note that `@i'
     cannot be handled by `deval'.
    @i
          unit of imaginary number

    @pi
          the number pi, the ratio of circumference to diameter

    @e
          Napier's number (exp(1))

     [118] eval(exp(@pi*@i));
     -1.0000000000000000000000000000
     [119] eval(2^(1/2));
     1.414213562373095048763788073031
     [120] eval(sin(@pi/3));
     0.86602540378443864674620506632
     [121] eval(sin(@pi/3)-3^(1/2)/2,50);
     -2.78791084448179148471 E-58
     [122] eval(1/2);
     1/2
     [123] deval(sin(1)^2+cos(1)^2);
     1

References
     *Note `ctrl': ctrl, *Note `setprec': setprec, *Note `pari': pari.

