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(71B) 3x3 Matrices: Determinant/Inverse/3x3 Systems - Eddie W. Shore - 06-29-2016 12:34 PM HP 71B 3x3 Matrices EWS 6/29/2016 The program MATX3 calculates: 1. The determinant and (if possible), the inverse of a 3x3 matrix M. 2. The solution to a 3x3 linear system: Mq=D. The determinant of M will also be displayed. If det(M) = 0, then the matrix is singular and execution stops. The matrix M is broken into three columns (3x1 arrays): [ M ] = [ A | B | C ]. Hence M = [[ A1 B1 C1 ] [ A2 B2 C2 ] [ A3 B3 C3 ]] Other variables used: E = det(M) I = M^-1. Unlike M, I will be a 3 x 3 array. R, K, S, H: other variables used Code:
Example: M = [[ 1, 2, -8 ] [ 0, -2, 9.5 ] [ 3.2, 2.7, -1 ]] D = [[ 0.5 ] [ 1.5 ] [ 2.5 ]] DET = -14.05 I ≈ [[ 1.6833, 1.3950, -0.2135 ] [ -2.1637, -1.7509, 0.6762 ] [ -0.4555, -0.2633, 0.1423 ]] Solutions: Q ≈ [[ 2.4004 ] [ -2.0178 ] [ -0.2669 ]] |