Isolating the real roots of a polynomial

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Determine the number of real roots of the following equation, and locate the intervals containing these roots:

x3−6x2+9x−10=0. x^{3}-6x^{2}+9x-10=0 .
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Determine the number of real roots of the following equation, and locate the intervals containing these roots:

x3−3x2−9x+h=0. x^{3}-3x^{2}-9x+h=0 .
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Determine the number of real roots of the following equation, and locate the intervals containing these roots:

3x4−4x3−6x2+12x−20=0. 3x^{4}-4x^{3}-6x^{2}+12x-20=0 .
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Determine the number of real roots of the following equation, and locate the intervals containing these roots:

x5−5x=a. x^{5}-5x=a .
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Isolate the real roots of the equation x3−12x+5=0x^{3}-12x+5=0.

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Isolate the real roots of the equation x3−27x−17=0x^{3}-27x-17=0.

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Isolate the real roots of the equation x4−2x3−5x2+2x+2=0x^{4}-2x^{3}-5x^{2}+2x+2=0.

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Isolate the real roots of the equation x4−2x3−5x2+3x+1=0x^{4}-2x^{3}-5x^{2}+3x+1=0.

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Isolate the real roots of the equation x5−2x4−5x3+19x2−17x+1=0x^{5}-2x^{4}-5x^{3}+19x^{2}-17x+1=0.

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Isolate the real roots of the equation x5+3x4−9x3−7x2+39x−21=0x^{5}+3x^{4}-9x^{3}-7x^{2}+39x-21=0.

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Isolate the roots of the equation, with respect to λ\lambda:

x2a2+λ+y2b2+λ+z2c2+λ−1=0,a2>b2>c2. \dfrac {x^{2}}{a^{2}+\lambda }+\dfrac {y^{2}}{b^{2}+\lambda }+\dfrac {z^{2}}{c^{2}+\lambda }-1=0, \quad a^{2} > b^{2} > c^{2} .
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Prove that all the roots of the derivative of the polynomial

P4(x)=(x+1)(x−1)(x−2)(x−3) P_{4}(x) = (x+1)(x-1)(x-2)(x-3)

are real, and find their isolation intervals of length at most 0.5.

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Prove that the polynomial:

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(1)

x5−2x4−x2−5=0x^{5}-2 x^{4}-x^{2}-5 = 0 has exactly one real root; indicate for this root an isolation interval of length at most 0.1;

(2)

x6+2x4+x−3=0x^{6}+2 x^{4}+x-3 = 0 has exactly two real roots; indicate for these roots isolation intervals of length at most 0.1.

Prove that the equation x5+x4+x2+10x−5=0x^{5}+x^{4}+x^{2}+10 x-5 = 0 has a unique root, and indicate its isolation interval of length not exceeding 0.1.

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Separate the real roots of the equation, indicating isolation intervals of length not exceeding unity:

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(1)

x3+2x−7=0x^{3}+2 x-7 = 0;

(2)

x3−27x−17=0x^{3}-27 x-17 = 0

(3)

x3−6x2+9x−10=0x^{3}-6 x^{2}+9 x-10 = 0;

(4)

x4−2x3−5x2+2x+2=0x^{4}-2 x^{3}-5 x^{2}+2 x+2 = 0;

(5)

x4−4x3−3x+23=0x^{4}-4 x^{3}-3 x+23 = 0

(6)

x4+6x3−2x2+1=0x^{4}+6 x^{3}-2 x^{2}+1 = 0

(7)

x5−10x3+6x+1=0x^{5}-10 x^{3}+6 x+1 = 0;

(8)

x5+5x3−7x+2=0x^{5}+5 x^{3}-7 x+2 = 0

(9)

x5+7x3−5x+11=0x^{5}+7 x^{3}-5 x+11 = 0

(10)

x5−2x4−5x3+19x2−17x+1=0x^{5}-2 x^{4}-5 x^{3}+19 x^{2}-17 x+1 = 0.

Separate the roots of the equation p2a2+x+q2b2+x+r2c2+x=1\frac{p^{2}}{a^{2}+x}+\frac{q^{2}}{b^{2}+x}+\frac{r^{2}}{c^{2}+x} = 1, where p,q,r,a,b,c∈R,a2>b2>c2,pqr≠0p, q, r, a, b, c \in \mathbb {R}, a^{2} > b^{2} > c^{2}, \quad p q r \neq 0.

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References

[Dem97] Demidovich B.P. Сборник задач и упражнений по математическому анализу. 13-е изд., Издательство Московского университета / Издательство "ЧеРо", 1997.
[ГюКу03] Гюнтер Н.М., Кузьмин Р.О. Сборник задач по высшей математике. 13-е изд., Издательство «Лань», 2003.
[ККЧ+03] Кудрявцев Л.Д., Кутасов А.Д., Чехлов В.И., Шабунин М.И. Предел. Непрерывность. Дифференцируемость. 2-е изд., ФИЗМАТЛИТ, 2003.