Gaussian Elimination-More Examples: Electrical Engineering
Gaussian Elimination-More Examples: Electrical Engineering
Gaussian Elimination-More Examples: Electrical Engineering
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Chapter 04.06<strong>Gaussian</strong> <strong>Elimination</strong> – <strong>More</strong> <strong>Examples</strong><strong>Electrical</strong> <strong>Engineering</strong>Example 1Three-phase loads are common in AC systems. When the system is balanced the analysis canbe simplified to a single equivalent circuit model. However, when it is unbalanced the onlypractical solution involves the solution of simultaneous linear equations. In one model thefollowing equations need to be solved.⎡0.7460− 0.4516 0.0100 − 0.0080 0.0100 − 0.0080⎤⎡Iar ⎤ ⎡ 120 ⎤⎢⎥ ⎢ ⎥ ⎢ ⎥⎢0.4516 0.7460 0.0080 0.0100 0.0080 0.0100⎢I⎥ai⎥ ⎢0.000⎥⎢0.0100− 0.0080 0.7787 − 0.5205 0.0100 − 0.0080⎥⎢I⎥br⎢−60.00⎥⎢⎥ ⎢ ⎥ = ⎢ ⎥⎢0.00800.0100 0.5205 0.7787 0.0080 0.0100 ⎥ ⎢Ibi ⎥ ⎢−103.9⎥⎢0.0100− 0.0080 0.0100 − 0.0080 0.8080 − 0.6040⎥⎢I⎥ ⎢−60.00⎥cr⎢⎥ ⎢ ⎥ ⎢ ⎥⎣0.00800.0100 0.0080 0.0100 0.6040 0.8080⎦ ⎢⎣Ici ⎥⎦⎣ 103.9⎦Find the values of Iar, Iai, Ibr, Ibi, Icr, and Iciusing naïve Gauss elimination.SolutionForward <strong>Elimination</strong> of UnknownsSince there are six equations, there will be five steps of forward elimination of unknowns.First stepDivide Row 1 by 0.7460 and multiply it by 0.4516, that is, multiply Row 1 by0 .4516 0.7460 = 0.60536 .Row 1×( 0.60536)=0.4516 − 0.27338 0.0060536 − 0.0048429 0.0060536 − 0.0048429 72.643Subtract the result from Row 2 to get⎡0.7460− 0.4516 0.0100 − 0.0080 0.0100 − 0.0080⎤⎡Iar ⎤ ⎡ 120 ⎤⎢⎥ ⎢ ⎥ ⎢ ⎥⎢0 1.0194 0.0019464 0.014843 0.0019464 0.014843⎢I⎥ai⎥ ⎢− 72.643⎥⎢0.0100− 0.0080 0.7787 − 0.5205 0.0100 − 0.0080⎥⎢I⎥br⎢ − 60.00 ⎥⎢⎥ ⎢ ⎥ = ⎢ ⎥⎢0.00800.0100 0.5205 0.7787 0.0080 0.0100 ⎥ ⎢Ibi ⎥ ⎢ −103.9⎥⎢0.0100− 0.0080 0.0100 − 0.0080 0.8080 − 0.6040⎥⎢I⎥ ⎢ − 60.00 ⎥cr⎢⎥ ⎢ ⎥ ⎢ ⎥⎣0.00800.0100 0.0080 0.0100 0.6040 0.8080⎦ ⎢⎣Ici ⎥⎦⎣ 103.9⎦[ ] [ ]04.06.1
04.06.2 Chapter 04.06Divide Row 1 by 0.7460 and multiply it by 0.0100, that is, multiply Row 1 by0 .0100 0.7460 = 0.013405.Row 1×0.013405 =( )[ 0.0100 − 0.0060536 0.00013405 − 0.00010724 0.00013405 − 0.00010724] [ 1.6086]Subtract the result from Row 3 to get⎡0.7460− 0.4516 0.0100⎢⎢0 1.0194 0.0019464⎢ 0 − 0.0019464 0.77857⎢⎢0.00800.0100 0.5205⎢0.0100− 0.0080 0.0100⎢⎣0.00800.0100 0.0080− 0.00800.014843− 0.520610.7787− 0.00800.01000.01000.00194640.00986600.00800.80800.6040− 0.0080 ⎤ ⎡I0.014843⎥ ⎢⎢I⎥− 0.0078928⎥⎢I⎥ ⎢0.0100 ⎥ ⎢I− 0.6040 ⎥ ⎢I⎥ ⎢0.8080⎦ ⎢⎣Iaraibrbicrci⎤ ⎡ 120 ⎤⎥ ⎢ ⎥⎥ ⎢− 72.643⎥⎥ ⎢−61.609⎥⎥ = ⎢ ⎥⎥ ⎢ −103.9⎥⎥ ⎢ − 60.00 ⎥⎥ ⎢ ⎥⎥⎦⎣ 103.9⎦Divide Row 1 by 0.7460 and multiply it by 0.0080, that is, multiply Row 1 by0 .0080 0.7460 = 0.010724 .Row 1×( 0.010724)=−5 −50.0080 − 0.0048429 0.00010724 − 8.5791×10 0.00010724 − 8.5791×10 1.2869Subtract the result from Row 4 to get⎡0.7460− 0.4516 0.0100 − 0.0080 0.0100 − 0.0080 ⎤ ⎡Iar ⎤ ⎡ 120 ⎤⎢⎥ ⎢ ⎥ ⎢ ⎥⎢0 1.0194 0.0019464 0.014843 0.0019464 0.014843⎢I⎥ai⎥ ⎢− 72.643⎥⎢ 0 − 0.0019464 0.77857 − 0.52061 0.0098660 − 0.0078928⎥⎢I⎥br⎢−61.609⎥⎢⎥ ⎢ ⎥ = ⎢ ⎥⎢ 0 0.014843 0.52039 0.77879 0.0078928 0.010086 ⎥ ⎢Ibi ⎥ ⎢−105.19⎥⎢0.0100− 0.0080 0.0100 − 0.0080 0.8080 − 0.6040 ⎥ ⎢I⎥ ⎢ − 60.00 ⎥cr⎢⎥ ⎢ ⎥ ⎢ ⎥⎣0.00800.0100 0.0080 0.0100 0.6040 0.8080⎦ ⎢⎣Ici ⎥⎦⎣ 103.9⎦[ ] [ ]Divide Row 1 by 0.7460 and multiply it by 0.0100, that is, multiply Row 1 by0 .0100 0.7460 = 0.013405.Row 1×( 0.013405)=[ 0.0100 − 0.0060536 0.00013405 − 0.00010724 0.00013405 − 0.00010724] [ 1.6086]Subtract the result from Row 5 to get⎡0.7460− 0.4516 0.0100 − 0.0080 0.0100 − 0.0080 ⎤ ⎡Iar ⎤ ⎡ 120 ⎤⎢⎥ ⎢ ⎥ ⎢ ⎥⎢0 1.0194 0.0019464 0.014843 0.0019464 0.014843⎢I⎥ai⎥ ⎢− 72.643⎥⎢ 0 − 0.0019464 0.77857 − 0.52061 0.0098660 − 0.0078928⎥⎢I⎥br⎢−61.609⎥⎢⎥ ⎢ ⎥ = ⎢ ⎥⎢ 0 0.014843 0.52039 0.77879 0.0078928 0.010086 ⎥ ⎢Ibi ⎥ ⎢−105.19⎥⎢ 0 − 0.0019464 0.0098660 − 0.0078928 0.80787 − 0.60389 ⎥ ⎢I⎥ ⎢−61.609⎥cr⎢⎥ ⎢ ⎥ ⎢ ⎥⎣0.00800.0100 0.0080 0.0100 0.6040 0.8080⎦ ⎢⎣Ici ⎥⎦⎣ 103.9⎦Divide Row 1 by 0.7460 and multiply it by 0.0080, that is, multiply Row 1 by0 .0080 0.7460 = 0.010724 .
<strong>Gaussian</strong> <strong>Elimination</strong>-<strong>More</strong> <strong>Examples</strong>: <strong>Electrical</strong> <strong>Engineering</strong> 04.06.3Row 1×( 0.010724)=−5 −5[ 0.0080 − 0.0048429 0.00010724 − 8.5791×10 0.00010724 − 8.5791×10 ] [ 1.2869]Subtract the result from Row 6 to get⎡0.7460− 0.4516 0.0100⎢⎢0 1.0194 0.0019464⎢ 0 − 0.0019464 0.77857⎢⎢ 0 0.014843 0.52039⎢ 0 − 0.0019464 0.0098660⎢⎣ 0 0.014843 0.0078928− 0.00800.014843− 0.520390.77879− 0.00789280.0100860.01000.00194640.00986600.00789280.807870.60389− 0.0080 ⎤ ⎡I0.014843⎥ ⎢⎢I⎥− 0.0078928⎥⎢I⎥ ⎢0.010086 ⎥ ⎢I− 0.60389 ⎥ ⎢I⎥ ⎢0.80809⎦ ⎢⎣ISecond stepDivide Row 2 by 1.0194 and multiply it by −0.0019464, that is, multiply Row 2 by− 0.00194641.0194 = −0.0019094.Row 2×− 0.0019094 =( )araibrbicrci⎤ ⎡ 120 ⎤⎥ ⎢ ⎥⎥ ⎢− 72.643⎥⎥ ⎢−61.609⎥⎥ = ⎢ ⎥⎥ ⎢−105.19⎥⎥ ⎢−61.609⎥⎥ ⎢ ⎥⎥⎦⎣ 102.61⎦−6 −5−6−5[ 0 − 0.0019464 − 3.7164×10 − 2.8341×10 − 3.7164×10 − 2.8341×10 ] [ 0.13870]Subtract the result from Row 3 to get⎡0.7460− 0.4516 0.0100⎢⎢0 1.0194 0.0019464⎢ 0 0 0.77857⎢⎢ 0 0.014843 0.52039⎢ 0 − 0.0019464 0.0098660⎢⎣ 0 0.014843 0.0078928− 0.00800.014843− 0.520360.77879− 0.00789280.0100860.01000.00194640.00986970.00789280.807870.60389− 0.0080 ⎤ ⎡I0.014843⎥ ⎢⎢I⎥− 0.0078644⎥⎢I⎥ ⎢0.010086 ⎥ ⎢I− 0.60389 ⎥ ⎢I⎥ ⎢0.80809⎦ ⎢⎣Iaraibrbicrci⎤ ⎡ 120 ⎤⎥ ⎢ ⎥⎥ ⎢− 72.643⎥⎥ ⎢−61.747⎥⎥ = ⎢ ⎥⎥ ⎢−105.19⎥⎥ ⎢−61.609⎥⎥ ⎢ ⎥⎥⎦⎣ 102.61 ⎦Divide Row 2 by 1.0194 and multiply it by 0.014843, that is, multiply Row 2 by0 .014843 1.0194 = 0.014561.Row 2×( 0.014561)=− 5−5[ 0 0.014843 2.8341×10 0.00021612 2.8341×10 0.00021612] [ −1.0577]Subtract the result from Row 4 to get⎡0.7460− 0.4516 0.0100 − 0.0080 0.0100 − 0.0080 ⎤ ⎡Iar⎤ ⎡ 120 ⎤⎢⎥ ⎢ ⎥ ⎢ ⎥⎢0 1.0194 0.0019464 0.014843 0.0019464 0.014843⎢I⎥ai⎥ ⎢− 72.643⎥⎢ 0 0 0.77857 − 0.52036 0.0098697 − 0.0078644⎥⎢I⎥br⎢−61.747⎥⎢⎥ ⎢ ⎥ = ⎢ ⎥⎢ 0 0 0.52036 0.77857 0.0078644 0.0098697 ⎥ ⎢Ibi⎥ ⎢−104.13⎥⎢ 0 − 0.0019464 0.0098660 − 0.0078928 0.80787 − 0.60389 ⎥ ⎢I⎥ ⎢−61.609⎥cr⎢⎥ ⎢ ⎥ ⎢ ⎥⎣ 0 0.014843 0.0078928 0.010086 0.60389 0.80809⎦ ⎢⎣Ici⎥⎦⎣ 102.61⎦Divide Row 2 by 1.0194 and multiply it by −0.0019464, that is, multiply Row 2 by− 0.00194641.0194 = −0.0019094.
04.06.4 Chapter 04.06Row 2×( − 0.0019094)=−6 −5−6−5[ 0 − 0.0019464 − 3.7164×10 − 2.8341×10 − 3.7164×10 − 2.8341×10 ] [ 0.13870]Subtract the result from Row 5 to get⎡0.7460− 0.4516 0.0100 − 0.0080⎢⎢0 1.0194 0.0019464 0.014843⎢ 0 0 0.77857 − 0.52036⎢⎢ 0 0 0.52036 0.77857⎢ 0 0 0.0098697 − 0.0078644⎢⎣ 0 0.014843 0.0078928 0.0100860.01000.00194640.00986970.00786440.807870.60389− 0.0080 ⎤ ⎡I0.014843⎥ ⎢⎢I⎥− 0.0078644⎥⎢I⎥ ⎢0.0098697 ⎥ ⎢I− 0.60386 ⎥ ⎢I⎥ ⎢0.80809⎦ ⎢⎣Iaraibrbicrci⎤ ⎡ 120 ⎤⎥ ⎢ ⎥⎥ ⎢− 72.643⎥⎥ ⎢−61.747⎥⎥ = ⎢ ⎥⎥ ⎢−104.13⎥⎥ ⎢−61.747⎥⎥ ⎢ ⎥⎥⎦⎣ 102.61⎦Divide Row 2 by 1.0194 and multiply it by 0.014843, that is, multiply Row 2 by0 .014843 1.0194 = 0.014561.Row 2×( 0.014561)=− 5−5[ 0 0.014843 2.8341×10 0.00021612 2.8341×10 0.00021612] [ −1.0577]Subtract the result from Row 6 to get⎡0.7460− 0.4516 0.0100 − 0.0080 0.0100 − 0.0080 ⎤ ⎡Iar⎤ ⎡ 120 ⎤⎢⎥ ⎢ ⎥ ⎢ ⎥⎢0 1.0194 0.0019464 0.014843 0.0019464 0.014843⎢I⎥ai⎥ ⎢− 72.643⎥⎢ 0 0 0.77857 − 0.52036 0.0098697 − 0.0078644⎥⎢I⎥br⎢−61.747⎥⎢⎥ ⎢ ⎥ = ⎢ ⎥⎢ 0 0 0.52036 0.77857 0.0078644 0.0098697 ⎥ ⎢Ibi⎥ ⎢−104.13⎥⎢ 0 0 0.0098697 − 0.0078644 0.80787 − 0.60386 ⎥ ⎢I⎥ ⎢−61.747⎥cr⎢⎥ ⎢ ⎥ ⎢ ⎥⎣ 0 0 0.0078644 0.0098697 0.60386 0.80787⎦ ⎢⎣Ici⎥⎦⎣ 103.67⎦Third stepDivide Row 3 by 0.77857 and multiply it by 0.52036, that is, multiply Row 3 by0 .52036 0.77857 = 0.66836 .Row 3×( 0.66836)=[ 0 0 0.52036 − 0.34779 0.0065965 − 0.0052563] [ − 41.269]Subtract the result from Row 4 to get⎡0.7460− 0.4516 0.0100 − 0.0080 0.0100 − 0.0080 ⎤ ⎡Iar⎤ ⎡ 120 ⎤⎢⎥ ⎢ ⎥ ⎢ ⎥⎢0 1.0194 0.0019464 0.014843 0.0019464 0.014843⎢I⎥ai⎥ ⎢− 72.643⎥⎢ 0 0 0.77857 − 0.52036 0.0098697 − 0.0078644⎥⎢I⎥br⎢−61.747⎥⎢⎥ ⎢ ⎥ = ⎢ ⎥⎢ 0 0 0 1.1264 0.0012679 0.015126 ⎥ ⎢Ibi⎥ ⎢−62.860⎥⎢ 0 0 0.0098697 − 0.0078644 0.80787 − 0.60386 ⎥ ⎢I⎥ ⎢−61.747⎥cr⎢⎥ ⎢ ⎥ ⎢ ⎥⎣ 0 0 0.0078644 0.0098697 0.60386 0.80787⎦ ⎢⎣Ici⎥⎦⎣ 103.67⎦Divide Row 3 by 0.77857 and multiply it by 0.0098697, that is, multiply Row 3 by0 .0098697 0.77857 = 0.012677 .
<strong>Gaussian</strong> <strong>Elimination</strong>-<strong>More</strong> <strong>Examples</strong>: <strong>Electrical</strong> <strong>Engineering</strong> 04.06.5Row 3×( 0.012677)=− 5[ 0 0 0.0098697 − 0.0065965 0.00012511 − 9.9695×10 ] [ − 0.78275]Subtract the result from Row 5 to get⎡0.7460− 0.4516 0.0100 − 0.0080⎢⎢0 1.0194 0.0019464 0.014843⎢ 0 0 0.77857 − 0.52036⎢⎢ 0 0 0 1.1264⎢ 0 0 0 − 0.0012679⎢⎣ 0 0 0.0078644 0.00986970.01000.00194640.00986970.00126790.807740.60386− 0.0080 ⎤ ⎡I0.014843⎥ ⎢⎢I⎥− 0.0078644⎥⎢I⎥ ⎢0.015126 ⎥ ⎢I− 0.60376 ⎥ ⎢I⎥ ⎢0.80787⎦ ⎢⎣Iaraibrbicrci⎤ ⎡ 120 ⎤⎥ ⎢ ⎥⎥ ⎢− 72.643⎥⎥ ⎢−61.747⎥⎥ = ⎢ ⎥⎥ ⎢−62.860⎥⎥ ⎢−60.965⎥⎥ ⎢ ⎥⎥⎦⎣ 103.67⎦Divide Row 3 by 0.77857 and multiply it by 0.0078644, that is, multiply Row 3 by0 .0078644 0.77857 = 0.010101.Row 3×( 0.010101)=− 5−5[ 0 0 0.0078644 − 0.0052563 9.9695×10 − 7.9439×10 ] [ − 0.62372]Subtract the result from Row 6 to get⎡0.7460− 0.4516 0.0100 − 0.0080 0.0100 − 0.0080 ⎤ ⎡Iar⎤ ⎡ 120 ⎤⎢⎥ ⎢ ⎥ ⎢ ⎥⎢0 1.0194 0.0019464 0.014843 0.0019464 0.014843⎢I⎥ai⎥ ⎢− 72.643⎥⎢ 0 0 0.77857 − 0.52036 0.0098697 − 0.0078644⎥⎢I⎥br⎢−61.747⎥⎢⎥ ⎢ ⎥ = ⎢ ⎥⎢ 0 0 0 1.1264 0.0012679 0.015126 ⎥ ⎢Ibi⎥ ⎢−62.860⎥⎢ 0 0 0 − 0.0012679 0.80774 − 0.60376 ⎥ ⎢I⎥ ⎢−60.965⎥cr⎢⎥ ⎢ ⎥ ⎢ ⎥⎣ 0 0 0 0.015126 0.60376 0.80795⎦ ⎢⎣Ici⎥⎦⎣ 104.29⎦Fourth stepDivide Row 4 by 1.1264 and multiply it by −0.0012679, that is, multiply Row 4 by− 0.00126791.1264 = −0.0011257.Row 4×( − 0.0011257)=−6 −5[ 0 0 0 − 0.0012679 −1.4273×10 −1.7027× 10 ] [ 0.070761]Subtract the result from Row 5 to get⎡0.7460− 0.4516 0.0100 − 0.0080 0.0100 − 0.0080 ⎤ ⎡Iar⎤ ⎡ 120 ⎤⎢⎥ ⎢ ⎥ ⎢ ⎥⎢0 1.0194 0.0019464 0.014843 0.0019464 0.014843⎢I⎥ai⎥ ⎢− 72.643⎥⎢ 0 0 0.77857 − 0.52036 0.0098697 − 0.0078644⎥⎢I⎥br⎢−61.747⎥⎢⎥ ⎢ ⎥ = ⎢ ⎥⎢ 0 0 0 1.1264 0.0012679 0.015126 ⎥ ⎢Ibi⎥ ⎢−62.860⎥⎢ 0 0 0 0 0.80775 − 0.60375 ⎥ ⎢I⎥ ⎢−61.035⎥cr⎢⎥ ⎢ ⎥ ⎢ ⎥⎣ 0 0 0 0.015126 0.60376 0.80795⎦ ⎢⎣Ici⎥⎦⎣ 104.29⎦Divide Row 4 by 1.1264 and multiply it by 0.015126, that is, multiply Row 4 by0 .015126 1.1264 = 0.013429 .
04.06.6 Chapter 04.06Row 4 ×( 0.013429)=− 5[ 0 0 0 0.015126 1.7027 × 10 0.00020313] [ − 0.84415]Subtract the result from Row 6 to get⎡0.7460− 0.4516 0.0100 − 0.0080⎢0 1.0194 0.0019464 0.014843⎢⎢ 0 0 0.77857 − 0.52036⎢⎢0 0 0 1.1264⎢ 0 0 0 0⎢⎣ 0 0 0 00.01000.00194640.00986970.00126790.807750.60375− 0.0080 ⎤ ⎡I0.014843⎥ ⎢I⎥ ⎢− 0.0078644⎥⎢I⎥ ⎢0.015126⎥ ⎢I− 0.60375 ⎥ ⎢I⎥ ⎢0.80775 ⎦ ⎣IFifth stepDivide Row 5 by 0.80775 and multiply it by 0.60375, that is, multiply Row 5 by0 .60375 0.80775 = 0.74745.Row 5×0.74741 =( )[ 0 0 0 0 0.60375 − 0.45127] [ − 45.621]Subtract the result from Row 6 to get⎡0.7460− 0.4516 0.0100 − 0.0080⎢0 1.0194 0.0019464 0.014843⎢⎢ 0 0 0.77857 − 0.52036⎢⎢0 0 0 1.1264⎢ 0 0 0 0⎢⎣ 0 0 0 00.01000.00194640.00986970.00126790.807750− 0.0080 ⎤ ⎡I0.014843⎥ ⎢I⎥ ⎢− 0.0078644⎥⎢I⎥ ⎢0.015126⎥ ⎢I− 0.60375 ⎥ ⎢I⎥ ⎢1.2590 ⎦ ⎣IThe six equations are0 .7460 Iar+ − 0.4516 Iai+ 0.0100Ibr+ − 0.0080 Ibi+ 0.0100Icr+ − 0.0080 Ici=1.0194Iai+ 0.0019464 Ibr+ 0.014843Ibi+ 0.0019464 Icr+ 0.014843Ici= −72.6430.77857Ibr− 0.52036Ibi+ 0.0098697 Icr+ ( − 0.0078644) Ici= −61.7471.1264Ibi+ 0.0012679 Icr+ 0.015126 Ici= −62.8600.80775Icr+ ( −0.60375)Ici= −61.0351 .2590 Ici= 150.75Back SubstitutionFrom the sixth equation1 .2590 Ici= 150.75150.75Ici=1.2590= 119.74Substituting the value of Iciin the fifth equation,.80775I+ ( −0.60375)I= −61.035araibrbicrciaraibrbicrci⎤ ⎡ 120 ⎤⎥ ⎢− 72.643⎥⎥ ⎢ ⎥⎥ ⎢−61.747⎥⎥ = ⎢ ⎥⎥ ⎢− 62.860⎥⎥ ⎢−61.035⎥⎥ ⎢ ⎥⎦ ⎣ 105.13 ⎦⎤ ⎡ 120 ⎤⎥ ⎢− 72.643⎥⎥ ⎢ ⎥⎥ ⎢−61.747⎥⎥ = ⎢ ⎥⎥ ⎢− 62.860⎥⎥ ⎢−61.035⎥⎥ ⎢ ⎥⎦ ⎣ 150.75 ⎦( ) ( ) ( ) 1200crci
<strong>Gaussian</strong> <strong>Elimination</strong>-<strong>More</strong> <strong>Examples</strong>: <strong>Electrical</strong> <strong>Engineering</strong> 04.06.7− 61.035− ( −0.60375)IciIcr=0.80775= 13.938Substituting the value of Icrand Iciin the forth equation,1.1264I0.0012679 I + 0.015126 I = −62.860bi+crci62.860− 0.0012679 Icr− 0.015126 Ici−Ibi=1.1264= −57.429Substituting the value of Ibi, Icrand Iciin the third equation,0 77857 I − 0.52036I+ 0.0098697 I + − 0.0078644 I = −61.( ) 747.brbicrci− 61.747+ 0.52036Ibi− 0.0098697 Icr− ( −0.0078644)Icibr=I0.77857= −116.66Substituting the value of Ibr, Ibi, Icrand Iciin the second equation,1.0194I 0.0019464 I + 0.014843I+ 0.0019464 I + 0.014843I= −72.643ai+brbicrci72.643− 0.0019464 Ibr− 0.014843Ibi− 0.0019464 Icr− 0.014843Ici−Iai=1.0194= −71.972Substituting the value of Iai, Ibr, Ibi, Icr, and Iciin the first equation,0 .7460 I ( −0.4516)I + 0.0100I+ ( −0.0080)I + 0.0100I+ ( −0.0080)I = 120ar+aibrbicrci120 − ( −0.4516)Iai− 0.0100Ibr− ( −0.0080)Ibi− 0.0100Icr− ( −0.0080)IciIar=0.7460= 119.33Hence the solution vector is⎡Iar ⎤ ⎡ 119.33 ⎤⎢I⎥ ⎢−⎥⎢ai71.972⎥ ⎢ ⎥⎢Ibr⎥ ⎢−116.66⎥⎢ ⎥ = ⎢ ⎥⎢Ibi ⎥ ⎢− 57.429⎥⎢I⎥ ⎢ 13.938 ⎥cr⎢ ⎥ ⎢ ⎥⎣Ici ⎦ ⎣ 119.74 ⎦SIMULTANEOUS LINEAR EQUATIONSTopic <strong>Gaussian</strong> <strong>Elimination</strong> – <strong>More</strong> <strong>Examples</strong>Summary <strong>Examples</strong> of <strong>Gaussian</strong> eliminationMajor <strong>Electrical</strong> <strong>Engineering</strong>Authors Autar KawDate June 15, 2010Web Site http://numericalmethods.eng.usf.edu