%%	help  is a very useful matlab command.  So is  lookfor
%%	try 'help' and 'help general' to see what help topics are available.

>> help if

 IF     Conditionally execute statements.
        The general form of an IF statement is:
                IF variable, statements, END
        The statements are executed if the real part of the variable 
        has all non-zero elements. The variable is usually the result of
        expr rop expr where rop is ==, <, >, <=, >=, or ~=.
        For example:
  
               IF I == J
                  A(I,J) = 2;
               ELSEIF ABS(I-J) == 1
                  A(I,J) = -1;
               ELSE
                  A(I,J) = 0;
               END

>> help for

 FOR    Repeat statements a specific number of times.
        The general form of a FOR statement is:
  
           FOR variable = expr, statement, ..., statement END
  
        The columns of the expression are stored one at a time in
        the variable and then the following statements, up to the
        END, are executed. The expression is often of the form X:Y,
        in which case its columns are simply scalars. Some examples
        (assume N has already been assigned a value).
  
             FOR I = 1:N,
                 FOR J = 1:N,
                     A(I,J) = 1/(I+J-1);
                 END
             END
  
        FOR S = 1.0: -0.1: 0.0, END steps S with increments of -0.1
        FOR E = EYE(N), ... END  sets E to the unit N-vectors.


%% do 'help lang' for more on flow-of-control constructs.
%% do 'help elfun' for more on elementary math functions.
%% do 'help ops' for operators and special characters.
%% do 'help matfun' for matrix functions.
%%
%%  each of these gives a list of topics for further help; e.g.

>> help eig

 EIG    Eigenvalues and eigenvectors.
        EIG(X) is a vector containing the eigenvalues of a square
        matrix X.
 
        [V,D] = EIG(X) produces a diagonal matrix D of
        eigenvalues and a full matrix V whose columns are the
        corresponding eigenvectors so that X*V = V*D.
  
        [V,D] = EIG(X,'nobalance') performs the computation with . . .