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Hints & Tips

DM32 Polynomial Solver

** From the Owner's Manual **

State File

Use

This set of programs will provide real and complex roots of polynomials up to 5th order. The coefficient of the highest term is assumed to be 1 and all the coefficients must be normalized to make this so.

Quadratic

'' x2 - 3x + 2 = 0 ''

  • Run XEQ P
  • Enter the order at the prompt for F? '' * 2 R/S * Enter coefficient ''B
    • 3 +/- R/S
  • Enter coefficient A
    • 2 R/S
  • 1st root is shown
    • X=1.0000 R/S
  • 2nd root is shown
    • X=2.0000 R/S
  • quits

The two roots of '' x2 - 3x + 2 = 0 '' are 1 and 2

4-th order

4x4 - 8x3 - 13x2 - 10x + 22 = 0

This has a non-unity value for the highest term, so all the coefficients need to be divided by 4 to make it so, this can be done as they are entered

  • XEQ P
  • Enter order 4 at the prompt for F? '' * 4 R/S * Enter the coefficients starting at the second one (for x3) and dividing by 4 * 8 +/- ENTER 4 ÷ R/S * 13 +/- ENTER 4 ÷ R/S * 10 +/- ENTER 4 ÷ R/S * 22 ENTER 4 ÷ R/S * The first root is shown * ''X = 0.88197 R/S
  • The second root is shown
    • X = 3.11803 R/S
  • The third root is shown (it's complex)
    • X=-1.0000 R/S
    • i = 1.0000R/S
  • The fourth root is shown (it's also complex)
    • X=1.0000 R/S
    • i=-1.0000 R/S
  • C

The 4 roots are

  • X = 0.88197
  • X = 3.11803
  • X = -1 + i1
  • X = 1 - i1

Cube roots of -8

'' X3 = -8''

'' X3 + 8 = 0 ''

  • XEQ P
  • Enter 3 for the order
    • 3 R/S
  • Enter zero for C (the coefficient of x2)
    • 0 R/S
  • Enter zero for B (the coefficient of x)
    • 0 R/S
  • Enter 8 for A (the constant term)
    • 8 R/S
  • The first root is
    • X = -2.00000 R/S
  • The second root is complex
    • '' X = 1.00000'' R/S
    • i = 1.73205 R/S
  • The third root is complex
    • X = 1.0000 R/S
    • i = -1.73205 R/S
  • Ctrl

The three cube roots of -8 are

  • -2
  • '' 1 + i 1.73205 ''
  • '' 1 - i 1.73205 ''

Further Information

Page created : 17/04/26 09:41 BST

Page updated : 17/04/26 10:09 BST