What is the area scaling factor for a transformation matrix M=(abcd)M = \begin{pmatrix} a & b \\ c & d \end{pmatrix}M=(acbd)?
∣a+d∣|a+d|∣a+d∣
∣ad−bc∣|ad - bc|∣ad−bc∣
a2+d2a^2 + d^2a2+d2
a2+b2+c2+d2\sqrt{a^2 + b^2 + c^2 + d^2}a2+b2+c2+d2