HP 33s hp 33s_user's manual_English_E_HDPM20PIE56.pdf - Page 240

Program Instructions: 1. Key in the program routines; press ‡ when done. 2. Press X A to input coefficients of matrix and column vector. 3. Key in coefficient or vector value (A through L) at each prompt and press g. 4. Optional: press X D to compute determinant of 3 × 3 system. 5. Press X I to compute inverse of 3 × 3 matrix. 6. Optional: press X A and repeatedly press g to review the values of the inverted matrix. 7. Press X M to multiply the inverted matrix by the column vector and to see the value of X. Press g to see the value of Y, then press g again to see the value of Z. 8. For a new case, go back to step 2. Variables Used: A through I J through L W X through Z i Coefficients of matrix. Column vector values. Scratch variable used to store the determinant. Output vector values; also used for scratch. Loop-control value (index variable); also used for scratch. Remarks: For 2 × 2 solutions use zero for coefficients C, F, H, G and for L. Use 1 for coefficient I. Not all systems of equations have solutions. Example: For the system below, compute the inverse and the system solution. Review the inverted matrix. Invert the matrix again and review the result to make sure that the original matrix is returned. 23X + 15Y + 17Z = 31 8X + 11Y - 6Z = 17 4X + 15Y + 12Z = 14 15-18 Mathematics Programs