Math Problem Statement

do me polynomial with 4 roots

Solution

To create a polynomial with 4 roots, let's follow this general rule:

If a polynomial has roots r1,r2,r3,r4r_1, r_2, r_3, r_4, then the polynomial can be written as:

P(x)=a(xr1)(xr2)(xr3)(xr4)P(x) = a(x - r_1)(x - r_2)(x - r_3)(x - r_4)

Here, aa is any non-zero constant (it affects the scaling of the polynomial, but not the roots).

Example:

Suppose we choose the roots as r1=1r_1 = 1, r2=2r_2 = -2, r3=3r_3 = 3, and r4=4r_4 = 4.

Then the polynomial will be:

P(x)=a(x1)(x+2)(x3)(x4)P(x) = a(x - 1)(x + 2)(x - 3)(x - 4)

For simplicity, let's set a=1a = 1:

P(x)=(x1)(x+2)(x3)(x4)P(x) = (x - 1)(x + 2)(x - 3)(x - 4)

Now, let's expand this expression:

[ P(x) = [(x - 1)(x + 2)] \cdot [(x - 3)(x - 4)] ]

First, expand the two binomials:

(x1)(x+2)=x2+x2(x - 1)(x + 2) = x^2 + x - 2 (x3)(x4)=x27x+12(x - 3)(x - 4) = x^2 - 7x + 12

Now multiply the two quadratic expressions:

P(x)=(x2+x2)(x27x+12)P(x) = (x^2 + x - 2)(x^2 - 7x + 12)

Expanding this:

P(x)=x47x3+12x2+x37x2+12x2x2+14x24P(x) = x^4 - 7x^3 + 12x^2 + x^3 - 7x^2 + 12x - 2x^2 + 14x - 24

Simplify the terms:

P(x)=x46x3+3x2+26x24P(x) = x^4 - 6x^3 + 3x^2 + 26x - 24

So the polynomial with roots 1, -2, 3, and 4 is:

P(x)=x46x3+3x2+26x24P(x) = x^4 - 6x^3 + 3x^2 + 26x - 24

Would you like more details or have any questions?

Here are 5 related questions:

  1. How do we determine the degree of a polynomial based on its roots?
  2. Can a polynomial have complex roots?
  3. What happens if the coefficient aa is not equal to 1?
  4. How can we factor a polynomial if the roots are known?
  5. What is the connection between the number of roots and the Fundamental Theorem of Algebra?

Tip: The sum of the roots of a polynomial axn+bxn1+ax^n + bx^{n-1} + \cdots is ba-\frac{b}{a}.

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Math Problem Analysis

Mathematical Concepts

Polynomials
Roots of Polynomials

Formulas

P(x) = a(x - r1)(x - r2)(x - r3)(x - r4)

Theorems

Fundamental Theorem of Algebra

Suitable Grade Level

Grades 10-12