Math, asked by DaRvl, 2 months ago

good morning❤️​❤️

plz solve it​

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Answers

Answered by shreemanlegendlive
7

Question :

Find the minors and cofactors of elements of the determinant

 \tt \left | \begin{array}{ccc} -1 & 0 & 4 \\ -2 & 1 & 3 \\ 0 & -4 & 2 \end{array} \right |

Solution:

Minors

 \tt  {M}_{11} = \left | \begin{array}{cc} 1 & 3 \\ -4 & 2 \end{array} \right |

 \tt \implies {M}_{11} = (1 ×2) - ( -4 ×3)

 \tt \implies {M}_{11} = 2 - (-12)

 \tt \implies {M}_{11} = 2 + 12

 \tt \therefore {M}_{11} = 14

 \tt  {M}_{12} = \left | \begin{array}{cc} -2 & 3 \\ 0 & 2 \end{array} \right |

 \tt  \implies {M}_{12} = ( 2 × -2) - (0 ×3)

 \tt  \implies {M}_{12} = -4 - 0

 \tt  \implies {M}_{12} = -4

 \tt  \therefore {M}_{12} = -4

 \tt  {M}_{13} = \left | \begin{array}{cc} -2& 1 \\ 0 & -4  \end{array} \right |

 \tt \implies {M}_{13} = (-2×-4)-(0×1)

 \tt \implies {M}_{13} = 8 - 0

 \tt \implies {M}_{13} = 8

 \tt \therefore {M}_{13} = 8

 \tt  {M}_{21} = \left | \begin{array}{cc} 0& 4 \\ -4 & 2  \end{array} \right |

 \tt \implies {M}_{21} = (0×2)-(4×-4)

 \tt \implies {M}_{21} = 0 - (-16)

 \tt \implies {M}_{21} = 16

 \tt \therefore {M}_{21} = 16

 \tt  {M}_{22} = \left | \begin{array}{cc} -1& 4 \\ 0 & 2  \end{array} \right |

 \tt \implies {M}_{22} = (-1×2)-(0×4)

 \tt \implies {M}_{22} = -2 - 0

 \tt \implies {M}_{22} = -2

 \tt \therefore {M}_{22} = -2

 \tt  {M}_{23} = \left | \begin{array}{cc} -1& 0 \\ 0 & -4 \end{array} \right |

 \tt \implies {M}_{23} = (0×-1) -(0×-4)

 \tt \implies {M}_{23} =0

 \tt \therefore {M}_{23} =0

 \tt  {M}_{31} = \left | \begin{array}{cc} 0& 1 \\ 4 & 3 \end{array} \right |

 \tt \implies {M}_{31} = (0×3) - (1×4)

 \tt \implies {M}_{31} = 0 - 4

 \tt \implies {M}_{31} =.-4

 \tt \therefore {M}_{31} = -4

 \tt  {M}_{32} = \left | \begin{array}{cc} -1& 4\\ -2& 3 \end{array} \right |

 \tt \implies {M}_{32} = (-1×3) - (4 ×-2)

 \tt \implies {M}_{32} = -3 +8

 \tt \implies {M}_{31} = 5

 \tt \therefore {M}_{32} = 5

 \tt  {M}_{32} = \left | \begin{array}{cc} -1& 0\\ -2& 1 \end{array} \right |

 \tt \implies {M}_{33} = (-1×-2)-(1×0)

 \tt \implies {M}_{33} = 2 - 0

 \tt \implies {M}_{32} = 2

 \tt \therefore {M}_{33} = 2

Cofactors :

 \tt {C}_{ij} = {-1}^{i+j}{M}_{ij}

\tt {C}_{11} ={-1}^{1+1}{M}_{11}

\tt \implies {C}_{11} ={-1}^{2}(14)

\tt \implies  {C}_{11} = 14

\tt \therefore {C}_{11} = 14

\tt {C}_{12} ={-1}^{1+2}{M}_{12}

 \tt \implies {C}_{12} = {-1}^{3}(-4)

 \tt \implies {C}_{12} = (-1)(-4)

 \tt \implies {C}_{12} = 4

 \tt \therefore {C}_{12} = 4

\tt {C}_{13} ={-1}^{1+3}{M}_{13}

 \tt \implies {C}_{13} = {-1}^{4}(8)

 \tt \implies {C}_{13} = 8

 \tt \therefore {C}_{13} = 8

\tt {C}_{21} ={-1}^{2+1}{M}_{21}

 \tt \implies {C}_{21} = {-1}^{3}(16)

 \tt \implies {C}_{21} = (-1)(16)

 \tt \implies {C}_{21} = -16

 \tt \therefore {C}_{21} = -16

\tt {C}_{22} ={-1}^{2+2}{M}_{22}

 \tt \implies {C}_{22} = {-1}^{4}(-2)

 \tt \implies {C}_{21} = 2

 \tt \therefore {C}_{21} = 2

\tt {C}_{23} ={-1}^{2+3}{M}_{23}

 \tt \implies {C}_{22} = {-1}^{5}(0)

 \tt \implies {C}_{21} = 0

 \tt \therefore {C}_{21} = 0

\tt {C}_{31} ={-1}^{3+1}{M}_{31}

 \tt \implies {C}_{22} = {-1}^{4}(-4)

 \tt \implies {C}_{21} = -4

 \tt \therefore {C}_{21} = -4

\tt {C}_{32} ={-1}^{3+2}{M}_{32}

 \tt \implies {C}_{22} = {-1}^{5}(2)

 \tt \implies {C}_{21} =- 2

 \tt \therefore {C}_{21} =- 2

\tt {C}_{33} ={-1}^{3+3}{M}_{33}

 \tt \implies {C}_{22} = {-1}^{6}(2)

 \tt \implies {C}_{21} = 2

 \tt \therefore {C}_{21} = 2

Answered by boss001gamer
2

Answer

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