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Calculate the nine cofactors of A=$\\var{matrixA}$?

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$A _{11}$ cofactor in position 1,1[[0]]

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$A_{12}$ cofactor in position 1,2[[1]]

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$A_{13}$ cofactor in position 1,3[[2]]

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$A_{21}$ cofactor in position 2,1[[3]]

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$A_{22}$ cofactor in position 2,2[[4]]

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$A_{23}$ cofactor in position 2,3[[5]]

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$A_{31}$ cofactor in position 3,1[[6]]

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$A_{32}$ cofactor in position 3,2[[7]]

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$A_{33}$ cofactor in position 3,3[[8]]

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What is the determinant of A=$\\var{matrixA}$?

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[[0]]

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What is the inverse of A=$\\var{matrixA}$? Enter your answers as fractions, not as decimals.

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[[0]]

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If \\[  A=\\left( \\begin{array}{ccc}
a & b & c \\\\d & e&f\\\\ g&h&j \\end{array} \\right),\\]

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Cofactors are given by \\[  A=\\left( \\begin{array}{ccc}
a & b & c \\\\d & e&f\\\\ g&h&j \\end{array} \\right),\\]

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Cof11 =\\[  +\\left| \\begin{array}{ccc}
e&f\\\\ h&j \\end{array} \\right|,\\]

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Cof12 =\\[  -\\left| \\begin{array}{ccc}
d & f\\\\ g&j \\end{array} \\right|,\\]

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Cof13 =\\[  +\\left| \\begin{array}{ccc}
d & e\\ g&h\\end{array} \\right|,\\]

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Cof21 =\\[ -\\left| \\begin{array}{ccc}
b & c \\\\h&j \\end{array} \\right|,\\]

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Cof22 =\\[  +\\left| \\begin{array}{ccc}
a  & c \\\\ g&j \\end{array} \\right|,\\]

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Cof23 =\\[  -\\left| \\begin{array}{ccc}
a & b \\\\g&h\\end{array} \\right|,\\]

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Cof31 =\\[  +=\\left| \\begin{array}{ccc}
b & c \\\\e&f\\end{array} \\right|,\\]

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Cof32 =\\[ -\\left| \\begin{array}{ccc}
a  & c \\\\d & f\\end{array} \\right|,\\]

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Cof33 =\\[  +\\left| \\begin{array}{ccc}
a & b\\\\d & e \\end{array} \\right|,\\]

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Then, the determinant of A is given by the sum of the product of any row ( or column) elements by their cofactors

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e.g row 1 determinant = a*cof11+b*cof12+c*cof13

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and the inverse of A is given by the ratio of the adjoint(A) and the deteminant of A

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where adjoint A= \\left( \\begin{array}{ccc}
cof11 & cof21 & cof31 \\\\cof12 & cof22&cof32\\\\ cof13&cof23&cof33 \\end{array} \\right),\\]

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  inverse of A=\\[  \\frac{1}{det(A)}*\\left( \\begin{array}{ccc}
cof11 & cof21 & cof31 \\\\cof12 & cof22&cof32\\\\ cof13&cof23&cof33 \\end{array} \\right),\\]

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\n

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cof23

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Cofactors Determinant and inverse of a 3x3 matrix.

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