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CASIO

User´s Guide

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Equation Calculations (EQN)

Quadratic and Cubic Equations

Quadratic Equation: ax2 + bx + c = 0

Cubic Equation: ax3 + bx2 + cx + d = 0

Entering the EQN Mode and pressing displays the initial quadratic/cubic equation screen.

Use this screen to specify 2 (quadratic) or 3 (cubic) as the degree of the equation, and input values for each of the coefficients.

(1) Coefficient name
(2) Element value
(3) Arrow indicates direction you should scroll to view other elements.

Any time until you input a value for the final coefficient (c for a quadratic equation, d for a cubic equation), you can use the and keys to move between coefficients on the screen and make changes, if you want.

Note that you cannot input complex numbers for coefficients.

Calculation starts and one of the solutions appears as soon as you input a value for the final coefficient.

(1) Variable name
(2) Solution
(3) Arrow indicates direction you should scroll to view other solutions.

Press the key to view other solutions. Use and to scroll between all of the solutions for the equation.

Pressing the key at this point returns to the coefficient input screen.

Certain coefficients can cause calculation to take more time.


Example 1: To solve the equation
x3 - 2x2 - x + 2 = 0 (x = 2, -1, 1)

(Degree?) 3
(a?) 1
(b?) 2
(c?) 1
(d?) 2
(x1 = 2)
(x2 = -1)
(x3 = 1)

If a result is a complex number, the real part of the first solution appears first. This is indicated by the "R↔I" symbol on the display. Press (Re⇔Im) to toggle the display between the real part and imaginary part of a solution.


Example 2: To solve the equation
8x2 - 4x + 5 = 0 (x = 0.25 ± 0.75i)

(Degree?) 2
(a?) 8
(b?) 4
(c?) 5
(x1 = 0.25 + 0.75i)
(x2 = 0.25 - 0.75i)
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