hi everyone.

Iam having a little trouble with mathematica. Everytime i pass in a matrix, which include a variable, i get an error.

eg. if i pass:

Det[{0, a, 0}, {a, 0, 0}, {1, 1, 1}]

i get the following error:

Det::nonopt: "Options expected (instead of {1,1,1}) beyond position 1 in "