Question

Suppose a and b are 3x3 matrices, with det(a) = 5 and det(b) = 3.

a. det(2a) = ? 4 pts
b. det((ab)-1) = ?

Answer 1

`\det(2\mathbf A)=2^3\det\mathbf A=8*5=40`


`\det(\mathbf{AB})^(-1)=\frac1{\det\mathbf{AB}}=\frac1{\det\mathbf A\det\mathbf B}=\frac1{5*3}=\frac1{15}`