Given polynomials p and q expressed in a Chebyshev basis, form the product  expressed in a Chebyshev basis.

All Chebyshev basis polynomials  which appear must have the same second argument x (which can be any expression).

The input polynomials must be in expanded form (i.e. a sum of products). Normally, each term in the sum contains one and only one  factor except that if there are terms in the sum containing no  factor then each such term t is interpreted to represent  provided that t and x have no variables in common.

If no  factor appears in p or in q then the ordinary product  is returned.

The command with(numapprox,chebmult) allows the use of the abbreviated form of this command.