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4th order polynomials 
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#1
Nov2810, 07:44 AM

P: 6

Hey everyone
Im doing control engineering and was wondering what methods i could use to find the roots of a 4th order polynomial? For example: (x^4) + (8x^3) + (7x^2) + 6x = 5 Could I seperate that into two brackets of quadratics or will i need to use a really long winded method? Thanks in advance for any help 


#2
Nov2810, 10:38 AM

P: 124

'order'? You mean 'degree'! Well yes there is a solution for it but it is indeed long winded. You can try to find easy solutions by try. Else use Maple or Matlab.



#3
Nov2810, 11:23 AM

HW Helper
P: 3,352

A formula exists for 4 degree polynomials analogously to the quadratic formula, but it is very long and complicated and coding it into a program would take too much time. Just numerically approximate all the roots.



#4
Nov2810, 11:46 AM

P: 6

4th order polynomials
Sorry, i do mean degree! Slipped up cos im working with a 4th order system.
I was worried id have to do it the long way. I did use Matlab but wanted to see if I could work out the answer by hand. Anywat, thanks for the help guys. I really appreciate it! 


#5
Jan3012, 03:05 PM

P: 2




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