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Math Function Problem

y=ax^5+bx^4+cx^3+dx^2+ex+f how to find x=f(y)

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#1 Abdelilah

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Posted 10 October 2021 - 08:03 AM

Hi all

 

I'm not a genius in math. So, any help is welcome :

 

I've this function :

 

y = a*x^5 + b*x^4 + c*x^3 + d*x^2 + e*x + f

 

My query is how to calculate x depending on y. I mean x=f(y).

 

Thanks in advance.


Edited by Abdelilah, 10 October 2021 - 08:03 AM.


#2 latexman

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Posted 10 October 2021 - 08:14 AM

Numerically, using Newton’s method.

#3 Pilesar

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Posted 10 October 2021 - 03:28 PM

It may not be the academic way, but I would put the y=f(x) function in Excel and use the 'goal seek' feature to target the y value desired by adjusting 'x'. If it did not find solution the first time, I would use a different initial estimate for 'x'. The Excel goal seek uses Newton's method and is pretty robust.



#4 breizh

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Posted 11 October 2021 - 07:34 AM

Hi,

Consider the paper attached within the link :

http://www.scielo.or...2n2/v52n2a9.pdf

 

note : let you try your favorite search  engine as I did .

 

Hope this is helping you

 

Breizh 






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