Álgebra linear Exemplos

[\begin{array}{c} 7 & 8 \\ \frac{2}{3} & \frac{1}{3} \end{array}]

$[\begin{array}{c} 7 & 8 \\ \frac{2}{3} & \frac{1}{3} \end{array}]$

Etapa 1

The inverse of a

2 \times 2

$2 \times 2$ matrix can be found using the formula

\frac{1}{a d - b c} [\begin{array}{c} d & - b \\ - c & a \end{array}]

$\frac{1}{a d - b c} [\begin{array}{c} d & - b \\ - c & a \end{array}]$ where

a d - b c

$a d - b c$ is the determinant.

Etapa 2

Find the determinant.

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Etapa 2.1

O determinante de uma matriz

2 \times 2

$2 \times 2$ pode ser encontrado ao usar a fórmula

| \begin{array}{c} a & b \\ c & d \end{array} | = a d - c b

$| \begin{array}{c} a & b \\ c & d \end{array} | = a d - c b$ .

7 (\frac{1}{3}) - \frac{2}{3} \cdot 8

$7 (\frac{1}{3}) - \frac{2}{3} \cdot 8$

Etapa 2.2

Simplifique o determinante.

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Etapa 2.2.1

Simplifique cada termo.

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Etapa 2.2.1.1

Combine

7

$7$ e

\frac{1}{3}

$\frac{1}{3}$ .

\frac{7}{3} - \frac{2}{3} \cdot 8

$\frac{7}{3} - \frac{2}{3} \cdot 8$

Etapa 2.2.1.2

Multiplique

- \frac{2}{3} \cdot 8

$- \frac{2}{3} \cdot 8$ .

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Etapa 2.2.1.2.1

Multiplique

8

$8$ por

- 1

$- 1$ .

\frac{7}{3} - 8 (\frac{2}{3})

$\frac{7}{3} - 8 (\frac{2}{3})$

Etapa 2.2.1.2.2

Combine

- 8

$- 8$ e

\frac{2}{3}

$\frac{2}{3}$ .

\frac{7}{3} + \frac{- 8 \cdot 2}{3}

$\frac{7}{3} + \frac{- 8 \cdot 2}{3}$

Etapa 2.2.1.2.3

Multiplique

- 8

$- 8$ por

2

$2$ .

\frac{7}{3} + \frac{- 16}{3}

$\frac{7}{3} + \frac{- 16}{3}$

\frac{7}{3} + \frac{- 16}{3}

$\frac{7}{3} + \frac{- 16}{3}$

Etapa 2.2.1.3

Mova o número negativo para a frente da fração.

\frac{7}{3} - \frac{16}{3}

$\frac{7}{3} - \frac{16}{3}$

\frac{7}{3} - \frac{16}{3}

$\frac{7}{3} - \frac{16}{3}$

Etapa 2.2.2

Combine os numeradores em relação ao denominador comum.

\frac{7 - 16}{3}

$\frac{7 - 16}{3}$

Etapa 2.2.3

Subtraia

16

$16$ de

7

$7$ .

\frac{- 9}{3}

$\frac{- 9}{3}$

Etapa 2.2.4

Divida

- 9

$- 9$ por

3

$3$ .

- 3

$- 3$

- 3

$- 3$

- 3

$- 3$

Etapa 3

Since the determinant is non-zero, the inverse exists.

Etapa 4

Substitute the known values into the formula for the inverse.

\frac{1}{- 3} [\begin{array}{c} \frac{1}{3} & - 8 \\ - \frac{2}{3} & 7 \end{array}]

$\frac{1}{- 3} [\begin{array}{c} \frac{1}{3} & - 8 \\ - \frac{2}{3} & 7 \end{array}]$

Etapa 5

Mova o número negativo para a frente da fração.

- \frac{1}{3} [\begin{array}{c} \frac{1}{3} & - 8 \\ - \frac{2}{3} & 7 \end{array}]

$- \frac{1}{3} [\begin{array}{c} \frac{1}{3} & - 8 \\ - \frac{2}{3} & 7 \end{array}]$

Etapa 6

Multiplique

- \frac{1}{3}

$- \frac{1}{3}$ por cada elemento da matriz.

[\begin{array}{c} - \frac{1}{3} \cdot \frac{1}{3} & - \frac{1}{3} \cdot - 8 \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{3} \cdot \frac{1}{3} & - \frac{1}{3} \cdot - 8 \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]$

Etapa 7

Simplifique cada elemento da matriz.

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Etapa 7.1

Multiplique

- \frac{1}{3} \cdot \frac{1}{3}

$- \frac{1}{3} \cdot \frac{1}{3}$ .

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Etapa 7.1.1

Multiplique

\frac{1}{3}

$\frac{1}{3}$ por

\frac{1}{3}

$\frac{1}{3}$ .

[\begin{array}{c} - \frac{1}{3 \cdot 3} & - \frac{1}{3} \cdot - 8 \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{3 \cdot 3} & - \frac{1}{3} \cdot - 8 \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]$

Etapa 7.1.2

Multiplique

3

$3$ por

3

$3$ .

[\begin{array}{c} - \frac{1}{9} & - \frac{1}{3} \cdot - 8 \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & - \frac{1}{3} \cdot - 8 \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]$

[\begin{array}{c} - \frac{1}{9} & - \frac{1}{3} \cdot - 8 \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & - \frac{1}{3} \cdot - 8 \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]$

Etapa 7.2

Multiplique

- \frac{1}{3} \cdot - 8

$- \frac{1}{3} \cdot - 8$ .

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Etapa 7.2.1

Multiplique

- 8

$- 8$ por

- 1

$- 1$ .

[\begin{array}{c} - \frac{1}{9} & 8 (\frac{1}{3}) \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & 8 (\frac{1}{3}) \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]$

Etapa 7.2.2

Combine

8

$8$ e

\frac{1}{3}

$\frac{1}{3}$ .

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]$

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ - \frac{1}{3} (- \frac{2}{3}) & - \frac{1}{3} \cdot 7 \end{array}]$

Etapa 7.3

Multiplique

- \frac{1}{3} (- \frac{2}{3})

$- \frac{1}{3} (- \frac{2}{3})$ .

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Etapa 7.3.1

Multiplique

- 1

$- 1$ por

- 1

$- 1$ .

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ 1 (\frac{1}{3}) \frac{2}{3} & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ 1 (\frac{1}{3}) \frac{2}{3} & - \frac{1}{3} \cdot 7 \end{array}]$

Etapa 7.3.2

Multiplique

\frac{1}{3}

$\frac{1}{3}$ por

1

$1$ .

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{1}{3} \cdot \frac{2}{3} & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{1}{3} \cdot \frac{2}{3} & - \frac{1}{3} \cdot 7 \end{array}]$

Etapa 7.3.3

Multiplique

\frac{1}{3}

$\frac{1}{3}$ por

\frac{2}{3}

$\frac{2}{3}$ .

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{3 \cdot 3} & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{3 \cdot 3} & - \frac{1}{3} \cdot 7 \end{array}]$

Etapa 7.3.4

Multiplique

3

$3$ por

3

$3$ .

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - \frac{1}{3} \cdot 7 \end{array}]$

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - \frac{1}{3} \cdot 7 \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - \frac{1}{3} \cdot 7 \end{array}]$

Etapa 7.4

Multiplique

- \frac{1}{3} \cdot 7

$- \frac{1}{3} \cdot 7$ .

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Etapa 7.4.1

Multiplique

7

$7$ por

- 1

$- 1$ .

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - 7 (\frac{1}{3}) \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - 7 (\frac{1}{3}) \end{array}]$

Etapa 7.4.2

Combine

- 7

$- 7$ e

\frac{1}{3}

$\frac{1}{3}$ .

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & \frac{- 7}{3} \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & \frac{- 7}{3} \end{array}]$

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & \frac{- 7}{3} \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & \frac{- 7}{3} \end{array}]$

Etapa 7.5

Mova o número negativo para a frente da fração.

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - \frac{7}{3} \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - \frac{7}{3} \end{array}]$

[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - \frac{7}{3} \end{array}]

$[\begin{array}{c} - \frac{1}{9} & \frac{8}{3} \\ \frac{2}{9} & - \frac{7}{3} \end{array}]$