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tien.lam12

What are the possible number of positive, negative, and complex zeros of f(x) = -3x4 - 5x3 - x2 - 8x + 4 ? A) Positive: 2 or 0; Negative: 2 or 0; Complex: 4 or 2 or 0 B) Positive: 1; Negative: 3 or 1; Complex: 2 or 0 C) Positive: 3 or 1; Negative: 1; Complex: 2 or 0 D) Positive: 4 or 2 or 0; Negative: 2 or 0; Complex: 4 or 2 or 0

  • one year ago
  • one year ago

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  1. ChukRock
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    the numbers after the x's are exponents, correct?

    • one year ago
  2. tien.lam12
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    yes

    • one year ago
  3. joeywhite
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    there are 2 positive and 2 complex roots

    • one year ago
  4. joeywhite
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    i've tried using descartes rule of signs but i got confused to be honest so i solved it

    • one year ago
  5. sahil51993
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    one root lie b/w 0 and 1

    • one year ago
  6. joeywhite
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    right

    • one year ago
  7. sahil51993
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    other will be negative as f(x) is increasing in R+

    • one year ago
  8. sahil51993
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    Am i right????

    • one year ago
  9. joeywhite
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    no 2 positive

    • one year ago
  10. sahil51993
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    yeah 1 will be positive and one will not be possitive it can also be possilbe that roots may be irrational becuase irrational roots also exist in pairs

    • one year ago
  11. estudier
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    there is 1 sign change so by DRS there is 1 positive root Sub -x for x to get negative roots, 3 sign changes so 3 or 1 negative roots Complex roots are total roots, 4, less positive and negative roots so 0 or 2 of those. Answer is B

    • one year ago
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