Returns the quotient of polynomial p(x) over q(x).
The last argument can be omitted for polynomials in x.
The remainder can be calculated by p-q*quotient(p,q).
If "a" is true then b is returned
else if c is true then d is returned, etc.
If the number of arguments is odd then the last argument is returned
when all else fails.
Returns the transpose of "a" with respect to indices i and j.
If i and j are omitted then 1 and 2 are used.
Hence a matrix can be transposed with a single argument.