线性代数示例

$[\begin{array}{c} 4 & - 7 & 4 \\ 0 & - 3 & 4 \\ 0 & - 8 & 9 \end{array}] - [\begin{array}{c} 4 & 0 & 0 \\ 0 & 4 & 0 \\ 0 & 0 & 4 \end{array}]$

解题步骤 1

减去相应的元素。

$[\begin{array}{c} 4 - 4 & - 7 - 0 & 4 - 0 \\ 0 - 0 & - 3 - 4 & 4 - 0 \\ 0 - 0 & - 8 - 0 & 9 - 4 \end{array}]$

解题步骤 2

Simplify each element.

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解题步骤 2.1

从 $4$ 中减去 $4$ 。

$[\begin{array}{c} 0 & - 7 - 0 & 4 - 0 \\ 0 - 0 & - 3 - 4 & 4 - 0 \\ 0 - 0 & - 8 - 0 & 9 - 4 \end{array}]$

解题步骤 2.2

从 $- 7$ 中减去 $0$ 。

$[\begin{array}{c} 0 & - 7 & 4 - 0 \\ 0 - 0 & - 3 - 4 & 4 - 0 \\ 0 - 0 & - 8 - 0 & 9 - 4 \end{array}]$

解题步骤 2.3

从 $4$ 中减去 $0$ 。

$[\begin{array}{c} 0 & - 7 & 4 \\ 0 - 0 & - 3 - 4 & 4 - 0 \\ 0 - 0 & - 8 - 0 & 9 - 4 \end{array}]$

解题步骤 2.4

从 $0$ 中减去 $0$ 。

$[\begin{array}{c} 0 & - 7 & 4 \\ 0 & - 3 - 4 & 4 - 0 \\ 0 - 0 & - 8 - 0 & 9 - 4 \end{array}]$

解题步骤 2.5

从 $- 3$ 中减去 $4$ 。

$[\begin{array}{c} 0 & - 7 & 4 \\ 0 & - 7 & 4 - 0 \\ 0 - 0 & - 8 - 0 & 9 - 4 \end{array}]$

解题步骤 2.6

从 $4$ 中减去 $0$ 。

$[\begin{array}{c} 0 & - 7 & 4 \\ 0 & - 7 & 4 \\ 0 - 0 & - 8 - 0 & 9 - 4 \end{array}]$

解题步骤 2.7

从 $0$ 中减去 $0$ 。

$[\begin{array}{c} 0 & - 7 & 4 \\ 0 & - 7 & 4 \\ 0 & - 8 - 0 & 9 - 4 \end{array}]$

解题步骤 2.8

从 $- 8$ 中减去 $0$ 。

$[\begin{array}{c} 0 & - 7 & 4 \\ 0 & - 7 & 4 \\ 0 & - 8 & 9 - 4 \end{array}]$

解题步骤 2.9

从 $9$ 中减去 $4$ 。

$[\begin{array}{c} 0 & - 7 & 4 \\ 0 & - 7 & 4 \\ 0 & - 8 & 5 \end{array}]$

解题步骤 3

Choose the row or column with the most $0$ elements. If there are no $0$ elements choose any row or column. Multiply every element in column $1$ by its cofactor and add.

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解题步骤 3.1

Consider the corresponding sign chart.

$| \begin{array}{c} + & - & + \\ - & + & - \\ + & - & + \end{array} |$

解题步骤 3.2

The cofactor is the minor with the sign changed if the indices match a $-$ position on the sign chart.

解题步骤 3.3

The minor for $a_{11}$ is the determinant with row $1$ and column $1$ deleted.

$| \begin{array}{c} - 7 & 4 \\ - 8 & 5 \end{array} |$

解题步骤 3.4

Multiply element $a_{11}$ by its cofactor.

$0 | \begin{array}{c} - 7 & 4 \\ - 8 & 5 \end{array} |$

解题步骤 3.5

The minor for $a_{21}$ is the determinant with row $2$ and column $1$ deleted.

$| \begin{array}{c} - 7 & 4 \\ - 8 & 5 \end{array} |$

解题步骤 3.6

Multiply element $a_{21}$ by its cofactor.

$0 | \begin{array}{c} - 7 & 4 \\ - 8 & 5 \end{array} |$

解题步骤 3.7

The minor for $a_{31}$ is the determinant with row $3$ and column $1$ deleted.

$| \begin{array}{c} - 7 & 4 \\ - 7 & 4 \end{array} |$

解题步骤 3.8

Multiply element $a_{31}$ by its cofactor.

$0 | \begin{array}{c} - 7 & 4 \\ - 7 & 4 \end{array} |$

解题步骤 3.9

Add the terms together.

$0 | \begin{array}{c} - 7 & 4 \\ - 8 & 5 \end{array} | + 0 | \begin{array}{c} - 7 & 4 \\ - 8 & 5 \end{array} | + 0 | \begin{array}{c} - 7 & 4 \\ - 7 & 4 \end{array} |$

解题步骤 4

将 $0$ 乘以 $| \begin{array}{c} - 7 & 4 \\ - 8 & 5 \end{array} |$ 。

$0 + 0 | \begin{array}{c} - 7 & 4 \\ - 8 & 5 \end{array} | + 0 | \begin{array}{c} - 7 & 4 \\ - 7 & 4 \end{array} |$

解题步骤 5

将 $0$ 乘以 $| \begin{array}{c} - 7 & 4 \\ - 8 & 5 \end{array} |$ 。

$0 + 0 + 0 | \begin{array}{c} - 7 & 4 \\ - 7 & 4 \end{array} |$

解题步骤 6

将 $0$ 乘以 $| \begin{array}{c} - 7 & 4 \\ - 7 & 4 \end{array} |$ 。

$0 + 0 + 0$

解题步骤 7

化简行列式。

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解题步骤 7.1

将 $0$ 和 $0$ 相加。

$0 + 0$

解题步骤 7.2

将 $0$ 和 $0$ 相加。

$0$

线性代数 示例

线性代数示例