Expansion Theorem for Determinants/Mistake

Source Work

 * cofactor
 * cofactor

Mistake

 * (i) The expression $a_{i1} A_{i1} + a_{i2} + \cdots + a_{in} A_{in}$ has the same value for any $i$, and is the definition of $\det \mathbf A$, the determinant of $\mathbf A$.

Correction
The expression should read:
 * $a_{i1} A_{i1} + a_{i2} A_{i2} + \cdots + a_{in} A_{in}$

In the $6$th edition, this section has been removed.