Talk:Signed area

Dubious

The following was removed:

The determinant

$$\det \left[{\begin{array}{cc}a&b\\c&d\end{array}}\right]=ac-bd$$

of a ${\textstyle 2\times 2}$ matrix whose entries ${\textstyle a,b,c,d}$ are real numbers is the signed area of the parallelogram whose sides are the vectors in the first and second columns of the matrix, the area being positive if the rotation from the direction of the ray in which the first column lies to the direction of the ray in which the second column lies is counterclockwise, and negative if clockwise.

Determinant is ad−bc, not given expression. Area assertion is dubious, not referenced. Rgdboer (talk) 22:52, 17 August 2023 (UTC)