**Defined in theory: Basic-matrix-algebra****Source code: basic-matrix.lisp**

**Documentation:**Function that returns the determinant of a matrix It has relevant informations such as if determinant = 0 the the matrix cannot be inverted

(=> (And (Square-Matrix ?M)) (= (Determinant ?M) (Cond ((= 1 (Size ?M)) (Value ?M 1 1)) ((< 1 (Size ?M)) (Summation (Lambda (?J) (* (Value ?M 1 ?J) (Cofactor ?M 1 ?J))) 1 (Size ?M))))))