# Is there a built-in function to find the adjoint of a matrix?

I've been looking for a function that helps me get the adjoint matrix o a given one, I found that you can get the cofactors of a matrix but only by using the "Combinatorica" package, which I couldn't get.

If you know any command or if you know effective ways of creating a function that does this, please help me.

• Can you explain what is the "adjunct"? – Szabolcs Nov 28 '13 at 1:30
• @Szabolcs Adjoint - in Spanish is "Adjunta" – Dr. belisarius Nov 28 '13 at 1:33
• Take a look at the help for Minors[], under "Applications" – Dr. belisarius Nov 28 '13 at 1:38
• I've found the translation "adjunt" so I wasn't sure it was the same "adjoint" – DavidBecharaSenior Nov 28 '13 at 1:39

This is just to get an answer on record so the question can be removed from not-answered list.

The following is taken from an example given in Application section of the documentation for Minors.

Define the adjoint of a matrix:

adj[m_] :=
Map[Reverse, Minors[Transpose[m], Length[m] - 1], {0, 1}] *
Table[(-1)^(i + j), {i, Length[m]}, {j, Length[m]}]

• Well done. But you're wrong: the question gets removed from the unanswered pile only after it has upvoted answers. Wait... now you're right :) – Dr. belisarius Nov 28 '13 at 4:40
• I realize there is a risk involved, but usually there is someone willing to take the bait :) – m_goldberg Nov 28 '13 at 12:44
• We're all for the rep here :) – Dr. belisarius Nov 28 '13 at 12:56
• @belisarius. Rep? What rep? This is pro bono work (CW). – m_goldberg Nov 28 '13 at 13:06
• That was the reason for my smiley! – Dr. belisarius Nov 28 '13 at 13:22

adj[m_] := Inverse[m] Det[m]

• Nicely done.$\phantom{}$ – J. M. is in limbo Jun 18 '15 at 13:05