Brian Dunning's FileMaker Custom Functions

Quartic_Solver ( a, b, c , d, e, which_x )

Finds Real Roots of Quartic Equation a*x^4 + b*x^3 + c*x^2 + d*x + e = 0

  Average rating: 3.5 (2 votes) Log in to vote

Dr. Ronald W. Satz   Dr. Ronald W. Satz
Transpower Corporation
http://www.transpowercorp.com

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  Sample input:
Let
(
[
a = -20 ;
b = 5 ;
c = 17 ;
d = -29 ;
e = 87 ;
which_x = 1
] ;

Quartic_Solver ( a ; b ; c ; d ; e ; which_x )
)
  Sample output:
1.48758311...

  Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

You can, of course, change the precision to whatever you want (or even take it off altogether). If the x you want is complex, you'll simply get a "?" for the result. For most problems in physical science, you will want a real root. But you may have to run the program up to four times to get the root which makes physical sense. Ref.: Wikipedia ("Quartic Function")

 

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