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Quadratic, Cubic and Quart Equations
Quadratic equation : ax
2
+ bx + c = 0 (a second-order polynomial
equation with a single variable x)
Cubic equation
: ax
3
+ bx
2
+ cx + d = 0 (an equation with cubic
polynomial)
Quart equation
: ax
4
+ bx
3
+ cx
2
+ dx + e = 0
For quadratic, cubic, or quartic equations, the variable name starts
with “X
1
”.
Example:
Solve the Cubic equation 5x
3
+ 2x
2
– 2x + 1 = 0
(Cubic equation)
X
1
=
X
2
=
X
3
=
Display
Key in operation
3
10
+0.331662479
3
10
-0.331662479
-1
Solve Function
■
Solve functions use Newton’s Method to obtain the approximate
solution of equations.
Note:
SOLVE function can be used in the COMP Mode only.
■
The following describes the types of equations whose solutions
can be obtained by using SOLVE function.
•
Equations that include variable X,
SOLVE function solves for X, for example,
X
2
+ 2X – 2, X = Y + 3,
X – 5 = A + B, X = tan(C),
•
Variable X to be solved should be put at the left hand side of
the equation.
For example, an equation is input as X
2
+ 5X = 24 or X
2
+ 5X – 24 = 0
or X
2
+ 5X – 24
•
An expression like X
2
+ 5X – 24 will be treated as X
2
+ 5X – 24 = 0,
not necessary to input “= 0”.
•
Equations input uses the following syntax :
{equation},{solution variable}
In general, an equation is solved for X, unless specified. For
example, to solve for Y when an equation is input as,
Y = X + 5, Y