Can't use invert(), function $ADJOINT is undefined

Hello:

I can't seem to use invert() to invert a matrix:

~~~
Maxima 5.9.1 http://maxima.sourceforge.net
Using Lisp GNU Common Lisp (GCL) GCL 2.6.6 (aka GCL)
Distributed under the GNU Public License. See the file
COPYING.
Dedicated to the memory of William Schelter.
This is a development version of Maxima. The function
bug_report()
provides bug reporting information.
Warning - you are redefining the MACSYMA function
EQUALP
Warning - you are redefining the MACSYMA function ODDP
Warning - you are redefining the MACSYMA function
EVENP
(%i1) A : matrix([1, 0], [0, 1])
;

                                   [ 1  0 ]
(%o1)                              [      ]
                                   [ 0  1 ]
(%i2) invert(A);

Maxima encountered a Lisp error:

 Error in MACSYMA-TOP-LEVEL [or a callee]: The
function $ADJOINT is undefined.

Automatically continuing.
To reenable the Lisp debugger set *debugger-hook* to
nil.

(%i3) A^^-1;

                                   [ 1  0 ]
(%o3)                              [      ]
                                   [ 0  1 ]

~~~~~~

Any ideas about how I can fix this?  Weird that the
^^-1 operator works, but the invert() function does
not.  I thought one was just an alias for the other.

Thanks,
Dan


		
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