Casio Graphing Calculators: Equation Variables
Introduction
Most modern Casio graphing calculators have an Equation solver mode that solves linear systems (Simultaneous), polynomials (Polynomial), and general equations.
To find run Equation mode, press [ MENU ] { A }*.
(*Equation mode is currently option A (fx-9750GIII, fx-CG 50, fx-CG 10/20, fx-9860 Slim))
Simultaneous Equations: SimRes and SimCoef
The simultaneous equation mode solves linear systems up to 6 x 6. The coefficients of the equations are stored in the variable Sim Coef (labeled SimCoef in VARS-EQUATION menu) while the results are stored in the variable Sim Result (labeled SimRes).
Polynomials: PlyRes and PlyCoef
The polynomial equation mode solves polynomials with real coefficients up to degree 6 (3 in early graphing models). The coefficients of the polynomial are stored in the variable Poly Coef (labeled PolyCoef in the VARS-EQUATION menu) while the results are stored in the variable Poly Result (labeled PolyRes).
Accessing Equation Variables Outside of Equation Mode
The four equation variables can be recalled by pressing [ VARS ], [ F6 ] { > }, [ EQUA ] { F3 }.
F1: SimRes (S·Rlt on older models)
F2: SimCoef (S·Cof on older models)
F3: PlyRes (P·Rlt on older models)
F4: PlyCof (P·Cof on older models)
The four variables are read-only matrices. We can not store values or information to read-only variables.
If we want to extract specific values from the equations variables, we must store them into a Matrix variable (A – Z, θ). For example, to retrieve the number from the 1st row and column of Sim Coef:
Sim Coef → Mat A
Mat A[1,1]
We can execute operations on equation variables. An interesting check is to run the simultaneous solver of the variable by typing:
Rref Sim Coef
and reading the last column.
Until next time,
Eddie
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