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3rd Degree Polynomial Calculator

Calculates a 3rd degree polynomial.

This is provided as a general formula that can be used by changing the constants.

screenshot

Example 1

For the polynomial Fx = -2 -1.5*x + 0.75*x^2 + 0.25*x^3

find f(3) and the roots.

Value Key Display Description
-2 C0 -2.0000 Stores the C0 value.
-1.5 C1 -1.5000 Stores the C1 value.
.75 C2 0.7500 Stores the C2 value.
.25 C3 0.2500 Stores the C3 value.
3 X 3.0000 Stores the X value.
  f(x) 7.0000 Calculates Fx(3).

Example 2

Find the root nearest to x = 3.

These keystrokes assume the values from example 1.

Value Key Display Description
0 f(x) 0.0000 Stores the Fx value.
  X 2.0000 Calculates a root.

Example 3

Find the root nearest to x = -3.

These keystrokes assume the values from examples 1 and 2.

Value Key Display Description
-3 X -3.0000 Stores a new initial guess.
  X -4.0000 Calculates a root.

Example 4

Find the root nearest to x = 0.

These keystrokes assume the values from examples 1 and 2.

Value Key Display Description
0 X 0.0000 Stores a new initial guess.
  X -1.0000 Calculates a root.

Graphing

Create a graph of for x = -5 to 3

Value Key Display Description
-5 = or ENTER -5.0000 Enters first value of the range.
3 shift f(x) graph Enters the second value of the range, selects the independent variable for the graph.

This will produce the following graph

Please see the Function Graph page on how to use the graph features.

Please note that the independent variable range can be entered in any order, minimum-maximum or maximum-minimum.

Reference:

Polynomial - Wikipedia