HP 50g HP 50g_user's manual_English_HDPSG49AEM8.pdf - Page 123

2x1 + 3x2 -5x3 = 13, x1 - 3x2 + 8x3 = -13, 2x1 - 2x2 + 4x3 = -6, can be written as the matrix equation A⋅x = b, if ⎡2 3 − 5⎤ ⎡ x1 ⎤ ⎡ 13 ⎤ A = ⎢⎢1 − 3 8 ⎥⎥, x = ⎢ ⎢ x2 ⎥⎥, and b 13⎥⎥. ⎢⎣2 − 2 4 ⎥⎦ ⎢⎣ x3 ⎥⎦ ⎢⎣ − 6 ⎥⎦ This system has the same number of equations as of unknowns, and will be referred to as a square system. In general, there should be a unique solution to the system. The solution will be the point of intersection of the three planes in the coordinate system (x1, x2, x3) represented by the three equations. To enter matrix A you can activate the Matrix Writer while the A: field is selected. The following screen shows the Matrix Writer used for entering matrix A, as well as the input form for the numerical solver after entering matrix A (press ` in the Matrix Writer): Press ˜ to select the B: field. The vector b can be entered as a row vector with a single set of brackets, i.e., [13,-13,-6] @@@OK@@@ . After entering matrix A and vector b, and with the X: field highlighted, we can press @SOLVE! to attempt a solution to this system of equations: Page 9-10