MaplePrimes - answers and comments on Question, display solution - symbolic

You are mixing new and old matrix commands.

Carl Love — Mon, 03 Dec 2012 08:04:52 Z

You are mixing new and old matrix commands. The new commands all begin with capital letters and tend to be spelled in full rather than abbreviated. Use Matrix and Vector instead of array. Use Adjoint instead of adjoint. Use Determinant instead of Det. See ?Matrix ?Vector ?Determinant etc.

with

Joe Riel — Mon, 03 Dec 2012 08:13:37 Z

The original poster should be aware that Determinant and Adjoint are members of the LinearAlgebra module. To access them in the short-form, use with(LinearAlgebra):

@Joe Riel Thank you both kindly for

ollyjg — Mon, 03 Dec 2012 10:20:08 Z

@Joe Riel

Thank you both kindly for your response. Having corrected the function calls within the worksheet it would notappear to be the source of the problem.

for example, running:

> with(LinearAlgebra);

> A := Matrix(3, 3, [[s*m-X[u], -s*X[wdot]+X[w], -(X[q]-m*W[e])*s+m*g*theta[e]], [-Z[u], -(Z[wdot]-m)*s-Z[w], -(Z[q]+m*U[e])*s+m*g*sin(theta[e])], [-M[u], -M[wdot]-M[w], I[y]*s^2-M[q]*s]]);

> B := Vector([X[eta], Z[eta], M[eta]]);

For simple commands such as

> Mutiply(Adjoint(A)/Determinant(A), b);

and

> Multiply(A, b);

I still recieve the outpus

[IMG]http://i46.tinypic.com/dbn9x.jpg[/IMG]

and

[IMG]http://i49.tinypic.com/27x4j0o.jpg[/IMG]

If possible I would like to obtain the solution itself.

Many thanks for you assitance.

guess

Joe Riel — Mon, 03 Dec 2012 10:49:54 Z

@ollyjg Multiply is spelled wrong, and Maple is case-sensitive, so you have to use B rather than b. However, that doesn't explain why Determinant and Adjoint did not evaluate. I'll guess that you didn't execute the with(LinearAlgebra); statement. If you did, and terminated it with a semicolon (use a colon to suppress the output), the worksheet would have displayed all the exports of LinearAlgebra.

multiple packages

PatrickT — Mon, 03 Dec 2012 14:45:35 Z

tip: (not a great tip, just my preference) I prefer to call the packages as I use them, this way 1) you remember which package does what, 2) if you copy-paste commands across your own worksheets, this ensures you also get the correct package loaded/called, 3) sometimes different packages use the same commands, so confusion could arise, you will get a "the blabla command is not part of the blibli package" which is helpful in keeping track of what you do 4) when you post for help on mapleprimes it's a lot clearer what you do where. I prefer to write in full LinearAlgebra:-Multiply, etc..

and in your case, if the with(LinearAlgebra); doesn't, for some reason, work properly, hopefully the "long" call to the command will.

@PatrickT Patrick, the 'long call'

ollyjg — Tue, 04 Dec 2012 03:47:35 Z

@PatrickT

Patrick, the 'long call' worked a charm.

Thanks to all for your assitance.

Cheers!!