Casio fx-991ZA Plus - Equation Calculations (EQN)

EN-31
Quadratic equation
3(aX
2
+ bX + c = 0)
Cubic equation
4(aX
3
+ bX
2
+ cX + d = 0)
3. Use the Coefficient Editor that appears to input coefficient values.
• To solve 2
x
2
+ x – 3 = 0, for example, press 3 in step 2, and then input
the following for the coefficients (
a = 2, b = 1, c = –3): 2=1=-
3=.
• To change a coefficient value you already have input, move the cursor
to the appropriate cell, input the new value, and then press =.
• Pressing A will clear all of the coefficients to zero.
Important: The following operations are not supported by the Coefficient
Editor: m, 1m(M–), 1t(STO). Pol, Rec, and multi-statements
also cannot be input with the Coefficient Editor.
4. After all the values are the way you want, press =.
• This will display a solution. Each press of = will display another
solution. Pressing = while the final solution is displayed will return to
the Coefficient Editor.
• You can scroll between the solutions using the c and f keys.
• To return to the Coefficient Editor while any solution is displayed, press
A.
Note: • Even if Natural Display is selected, the solutions of simultaneous
linear equations are not displayed using any form that includes '.
• Values cannot be converted to engineering notation on the solution screen.
• A message appears to let you know when there is no solution or when
there are infinite solutions. Pressing A or = will return to the Coefficient
Editor.
Changing the Current Equation Type Setting
Press N5(EQN) and then select an equation type from the menu that
appears. Changing the equation type causes the values of all Coefficient
Editor coefficients to change to zero.
EQN Mode Calculation Examples
x + 2y = 3, 2x + 3y = 4
N5(EQN)1(a
n
X + b
n
Y = c
n
)
1 = 2 = 3 =
2 = 3 = 4 =
=
(X=) –1
c (Y=) 2
x – y + z = 2, x + y – z = 0, –x + y + z = 4
N5(EQN)2(a
n
X + b
n
Y + c
n
Z = d
n
)
1 =- 1 = 1 = 2 =
1 = 1 =- 1 =0 =
- 1 = 1 = 1 = 4 =
=
(X=) 1
c (Y=) 2
c (Z=) 3
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