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jeremy

  • 5 years ago

find the roots of f(x)=x^4-6x^3-10x^2+2x-15

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  1. anonymous
    • 5 years ago
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    i have the same problem

  2. anonymous
    • 5 years ago
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    there are 4 roots in this

  3. anonymous
    • 5 years ago
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    x ~~ -1.9134607252052312 x ~~ 7.3594940468468407 x ~~ 0.27698333917919524-0.99421429099634553 i x ~~ 0.27698333917919524+0.99421429099634553 i are the four roots, and th elast two are imaginary, ( the reason i've typed an 'i' there)

  4. amistre64
    • 5 years ago
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    there are ways you can improve your odds when searching for roots; I forget the names they give to them, but, it has something to do with the number of times the signs switch; and factors and fractions of first/last....

  5. amistre64
    • 5 years ago
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    1,3,5,15 -1,-3,-5,-15 then use synthetic division to weed them out if possible :)

  6. anonymous
    • 5 years ago
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    yes u r right, amistre

  7. anonymous
    • 5 years ago
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    the highest power x has , is the no. of roots u get

  8. amistre64
    • 5 years ago
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    the number of "possible" roots, yes.... but we can have no roots as well :)

  9. anonymous
    • 5 years ago
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    no roots at all ? not even imaginary ??

  10. amistre64
    • 5 years ago
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    "we dont need no stinkin' toots" - anonymous take x^2 +5 for example, .... ro :real" roots :)

  11. amistre64
    • 5 years ago
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    urg!!....roots lol

  12. anonymous
    • 5 years ago
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    hmmm

  13. amistre64
    • 5 years ago
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    i feel like i have an iphone doing atuo correct on me lol

  14. anonymous
    • 5 years ago
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    ha ha h a

  15. anonymous
    • 5 years ago
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    Refer to the attachment, jeremy.pdf The two real roots are clearly visible. Thinker has them nailed. The root 7.35.. yields a function value very close to zero. \[f(7.35949) = 1.13687 * 10^{-13}\] By eye ball, one can see where the three derivatives are zero and the two inflection points. P.S. If everyone had access to a copy of Mathematica V8, I would venture to guess that there would be very few problems posted to this site. I have no financial connections to Wolfram.

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