Sharp EL-9900 - Manual (Page 63)

10
Advanced Keyboard/ALGEBRA USING THE SHARP EL-9900
Copyright © 2002, Sharp Electronics Corporation. Permission is granted to photocopy for educational use only.
1. The calculator will directly establish an identity matrix of a given size by
pressing 2ndF MATRIX C (OPE) 0 5 (identity) and pressing 3
ENTER . To save the identity matrix in matrix C, press STO 2ndF
MATRIX A (NAME) 3 (mat C) ENTER . Confirm that the identity matrix
is stored in matrix C by pressing 2ndF MATRIX B (EDIT) 3 (mat C).
Press 2ndF QUIT to exit the matrix editor and press CL to clear
the screen.
2. Find the inverse of the square matrix A by pressing 2ndF MATRIX
A (NAME) 1 (mat A) 2ndF x- 1 ENTER . Press to see more of
the matrix.
3. To solve the system of equations x + 2y + z = 8
2x + y – z = 1
x + y – 2z = -3
using matrices, use the matrix A entered previously as the coefficient matrix,
and enter the constants on the right side of the equal sign into matrix B,
where B = 8
1
-3 .
Press 2ndF QUIT to exit the display of the B matrix. The solution matrix
X is found by multiplying mat A -1 B • mat B.
4. This multiplication is derived from the equation AX= B,
A -1 • A • X = A -1 • B (multiply both sides by A -1 )
I • X = A -1 • B (A -1 • A = I, identity matrix)
X = A -1 • B (I • X = X )
Multiply A -1 • B by pressing 2ndF MATRIX A (NAME) 1 (mat A)
2ndF x- 1 × 2ndF MATRIX A (NAME) 2 (mat B) and ENTER .
The solution matrix will appear.
MATRIC SOLUTIONS TO
SYSTEMS OF LINEAR EQUATIONS
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