% , True, False , EndOfFile , Infinity , Pi , Undefined .

Constants

% previous result
True, False boolean constants
EndOfFile end-of-file marker
Infinity constant representing mathematical infinity
Pi mathematical constant, pi
Undefined constant signifying an undefined result

% -- previous result

Internal function
Calling format: 
%

Description:
% evaluates to the previous result on the command line. % is a global variable that is bound to the previous result from the command line. Using % will evaluate the previous result. (This uses the functionality offered by the LazyGlobal command).

Typical examples are Simplify(%) and PrettyForm(%) to simplify and show the result in a nice form respectively.

Examples: 
In> Taylor(x,0,5)Sin(x)
Out> x-x^3/6+x^5/120;
In> PrettyForm(%)

     3    5
    x    x
x - -- + ---
    6    120

See also:
LazyGlobal .

True, False -- boolean constants

Internal function
Calling format: 
True
False

Description:
True and False are typically a result of boolean expressions such as 2 < 3 or True And False.

See also:
And , Or , Not .

EndOfFile -- end-of-file marker

Internal function
Calling format: 
EndOfFile

Description:
End of file marker when reading from file. If a file contains the expression EndOfFile; the operation will stop reading the file at that point.

Infinity -- constant representing mathematical infinity

Standard library
Calling format: 
Infinity

Description:
Infinity represents infinitely large values. It can be the result of certain calculations.

Note that for most analytic functions Yacas understands Infinity as a positive number. Thus Infinity*2 will return Infinity, and a < Infinity will evaluate to True.

Examples: 
In> 2*Infinity
Out> Infinity;
In> 2<Infinity
Out> True;

Pi -- mathematical constant, pi

Standard library
Calling format: 
Pi

Description:
Pi symbolically represents the exact value of pi. When the N() function is used, Pi evaluates to a numerical value according to the current precision. This is performed by the function Pi() which always returns the numerical value. It is probably better to use Pi than Pi(), because exact simplification will be possible.

Examples: 
In> Sin(3*Pi/2)
Out> -1;
In> Sin(3*Pi()/2)
Out> Sin(4.7123889804);
In> Pi+1
Out> Pi+1;
In> N(Pi)
Out> 3.14159265358979323846;

See also:
Sin , Cos , Precision , N , Pi() .

Undefined -- constant signifying an undefined result

Standard library
Calling format: 
Undefined

Description:
Undefined is a token that can be returned by a function when it considers its input to be invalid or when no meaningful answer can be given. The result is then "undefined".

Most functions also return Undefined when evaluated on it.

Examples: 
In> 2*Infinity
Out> Infinity;
In> 0*Infinity
Out> Undefined;
In> Sin(Infinity);
Out> Undefined;
In> Undefined+2*Exp(Undefined);
Out> Undefined;

See also:
Infinity .