- #1

Loonygirl

- 5

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Use Descartes' Rule of Signs to analyze the zeros of the following. List all possibilities.

1. P(x) = x5 - 4x4 + 3x3 + 2x - 6

2. P(x) = -5x4 + x3 + 2x2 - 1

3. P(x) = 2x5 + 7x3 + 6x2 - 2

So I found these answers, are they right?:

1. P(x) = x^5 - 4x^4 + 3x^3 + 2x - 6

(3 positive, 2 imaginary) ; (1 positive, 4 imaginary)

2. P(x) = -5x^4 + x^3 + 2x^2 - 1

(2 positive, 2imaginary) ; (4imaginary) ; (2 positive, 2 negative) ; (2 neg. 2 imagin.)

3. P(x) = 2x^5 + 7x^3 + 6x^2 - 2

(1 positive, 4 imaginary) ; (1 positive, 2 negative, 2 imaginary)

1. P(x) = x5 - 4x4 + 3x3 + 2x - 6

2. P(x) = -5x4 + x3 + 2x2 - 1

3. P(x) = 2x5 + 7x3 + 6x2 - 2

So I found these answers, are they right?:

1. P(x) = x^5 - 4x^4 + 3x^3 + 2x - 6

(3 positive, 2 imaginary) ; (1 positive, 4 imaginary)

2. P(x) = -5x^4 + x^3 + 2x^2 - 1

(2 positive, 2imaginary) ; (4imaginary) ; (2 positive, 2 negative) ; (2 neg. 2 imagin.)

3. P(x) = 2x^5 + 7x^3 + 6x^2 - 2

(1 positive, 4 imaginary) ; (1 positive, 2 negative, 2 imaginary)

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