t is not defined. A constraint is not a definition.

Your other problem is that Mathcad does not do the sort of matrix calculations that you are asking for. The exp function cannot be applied to a matrix. And in your actual sheet, you are not even attempting to do so -- if you look at the actual expression you will find that you have an implicit multiplication there, so you are multiplying exp by a matrix. That doesn't work as functions cannot be used arithmetically. The parenthesis that are used to denote arrays cannot also denote function application. You need separate parentheses for that. Not that it matters in this case, as the exponential of a matrix is not built into Mathcad, and you would have to define it separately (I've posted a worksheet that shows how to do that at

http://collab.mathsoft.com/read?40727,11 ).

However, even that will not solve your problems, as Mathcad does not integrate vectors. Only scalars. You must either reduce the problem to a set of scalar integrals or write your own integration routines.

Before you use an expression in a constraint in a solve block, you should make sure that it evaluates properly outside the solve block.

Tom Gutman