The product of three numbers on the solid line takes the positive sign, and three items on the dotted line take the negative sign, and there are three items.

Extended data:

Diagonal rule is mainly used in chemistry, mathematics, photography and Guoqi.

mathematics

Diagonal rule is usually used to calculate the values of second-order and third-order determinants.

The following two methods are commonly used to calculate the value of n-order n≥4) determinant:

1. Applying property 7, all elements below the main diagonal become 0, which becomes an upper triangular determinant.

Its value is equal to b 1 1b22 bnn.

2. Select a row (column), change all the other n- 1 elements of the row (column) to 0 except one non-zero element, and then expand the row (column) [Theorem 8] to simplify the n-order determinant to n- 1 order determinant.

References:

Baidu encyclopedia-diagonal rule