octave:26> A = [A, ones(10,1 > )] A = Columns 1 through 7: 0.947835 0.326209 0.559327 0.012554 0.615261 0.612343 0.545748 0.053559 0.223562 0.019903 0.343954 0.202994 0.982246 0.286222 0.189272 0.342542 0.199935 0.774843 0.069270 0.367443 0.805417 0.201355 0.912303 0.795006 0.340036 0.159216 0.860521 0.108482 0.551106 0.536611 0.594476 0.259730 0.141622 0.124129 0.045184 0.318537 0.856273 0.203674 0.530649 0.527614 0.264191 0.125989 0.263587 0.160872 0.271627 0.790913 0.287855 0.178326 0.703146 0.521926 0.073149 0.265289 0.389933 0.209417 0.569251 0.615992 0.371961 0.046063 0.574667 0.218591 0.935108 0.469189 0.843883 0.888469 0.829204 0.063051 0.672222 0.170393 0.022979 0.059819 Columns 8 through 11: 0.102727 0.021924 0.886309 1.000000 0.050214 0.668191 0.144928 1.000000 0.902398 0.194649 0.909168 1.000000 0.818384 0.631662 0.823301 1.000000 0.117174 0.132058 0.364935 1.000000 0.247341 0.045387 0.678265 1.000000 0.377743 0.951132 0.705329 1.000000 0.539119 0.257853 0.279668 1.000000 0.986533 0.180929 0.478485 1.000000 0.490385 0.061855 0.761491 1.000000 octave:27> A=[A; 2.*ones(1,11)] A = Columns 1 through 7: 0.947835 0.326209 0.559327 0.012554 0.615261 0.612343 0.545748 0.053559 0.223562 0.019903 0.343954 0.202994 0.982246 0.286222 0.189272 0.342542 0.199935 0.774843 0.069270 0.367443 0.805417 0.201355 0.912303 0.795006 0.340036 0.159216 0.860521 0.108482 0.551106 0.536611 0.594476 0.259730 0.141622 0.124129 0.045184 0.318537 0.856273 0.203674 0.530649 0.527614 0.264191 0.125989 0.263587 0.160872 0.271627 0.790913 0.287855 0.178326 0.703146 0.521926 0.073149 0.265289 0.389933 0.209417 0.569251 0.615992 0.371961 0.046063 0.574667 0.218591 0.935108 0.469189 0.843883 0.888469 0.829204 0.063051 0.672222 0.170393 0.022979 0.059819 2.000000 2.000000 2.000000 2.000000 2.000000 2.000000 2.000000 Columns 8 through 11: 0.102727 0.021924 0.886309 1.000000 0.050214 0.668191 0.144928 1.000000 0.902398 0.194649 0.909168 1.000000 0.818384 0.631662 0.823301 1.000000 0.117174 0.132058 0.364935 1.000000 0.247341 0.045387 0.678265 1.000000 0.377743 0.951132 0.705329 1.000000 0.539119 0.257853 0.279668 1.000000 0.986533 0.180929 0.478485 1.000000 0.490385 0.061855 0.761491 1.000000 2.000000 2.000000 2.000000 2.000000 octave:28> inv(A) ans = Columns 1 through 6: 0.270814 0.674332 0.071985 -0.519663 0.493485 -1.598266 0.860762 -53.234210 -40.316263 26.637925 -45.809125 58.743268 -0.596111 22.783023 17.968934 -11.611910 21.470848 -25.501045 -1.727914 53.475766 41.133369 -27.452322 46.663775 -57.910690 -0.339689 14.816224 10.492875 -7.597423 12.225363 -15.373886 -0.204835 22.020126 16.529853 -10.618306 18.109803 -23.465573 1.286745 -53.416453 -39.679434 26.042935 -45.720498 58.367671 -0.431969 -1.393581 -1.103373 1.181156 -1.602440 0.764942 0.335794 -18.202197 -14.756988 9.658051 -16.295043 19.460792 0.523906 18.213568 14.324764 -8.738131 15.135222 -20.218128 0.022496 -5.736598 -4.665720 3.017687 -4.671390 6.730917 Columns 7 through 11: -0.434014 -0.895144 0.282250 1.275471 0.189375 24.126292 95.987582 -29.244338 -26.969647 -5.391124 -10.883358 -42.021307 12.455994 10.715723 2.609604 -24.867659 -96.237164 28.540405 26.619334 5.881550 -6.618487 -27.019963 8.757537 7.496102 1.580673 -10.586944 -38.442402 11.306484 10.618189 2.366803 24.434183 96.454801 -29.315917 -27.685337 -5.384347 0.408167 2.376864 0.053264 0.182792 -0.217911 9.417732 32.865051 -9.803681 -8.758810 -1.960351 -7.988733 -34.093553 9.887193 9.470576 1.741658 2.992821 11.025236 -2.919193 -2.964392 -0.915931 octave:29> B = inv(A)(:, [2,4]) B = 0.67433 -0.51966 -53.23421 26.63793 22.78302 -11.61191 53.47577 -27.45232 14.81622 -7.59742 22.02013 -10.61831 -53.41645 26.04293 -1.39358 1.18116 -18.20220 9.65805 18.21357 -8.73813 -5.73660 3.01769 octave:30> diary off