The sum and product of an nth degree polynomial

In summary, the conversation discusses the proof of the sum and product of the roots of a monic polynomial. The proof involves multiplying out the polynomial and counting powers of x. This assumes knowledge of the Fundamental Theorem of Algebra and basic polynomial multiplication.
  • #1
phyguy321
45
0

Homework Statement


Suppose f(x) [tex]\in[/tex] Complex[x] is a monic polynomial of degree n with roots c1,c2,...cn. Prove that the sum of the roots is -a[tex]_{n-1}[/tex] and their product is (-1)[tex]^{n}[/tex]a[tex]_{0}[/tex]

Homework Equations





The Attempt at a Solution


(x-c1)(x-c2)...(x-cn) = x[tex]^{n}[/tex] + (c1+c2+...+cn)x[tex]^{n-1}[/tex]...(c1*c2*...*cn)

I just need a realistic proof this assumes too much
 
Physics news on Phys.org
  • #2
In what way do you think that's assuming too much? Do you know the Fundamental Theorem of Algebra?
 
  • #3
but how do i know that (x-c1)(x-c2)...(x-cn) = xLaTeX Code: ^{n} + (c1+c2+...+cn)xLaTeX Code: ^{n-1} ...(c1*c2*...*cn)?
 
  • #4
Count powers of x. There's only one way to make x^n and x^0. There are n ways to make x^1. You just imagine multiplying it out.
 
  • #5
phyguy321 said:
but how do i know that (x-c1)(x-c2)...(x-cn) = xLaTeX Code: ^{n} + (c1+c2+...+cn)xLaTeX Code: ^{n-1} ...(c1*c2*...*cn)?

Because you know how to multiply polynomials?
 
  • #6
so that's a legit proof then?
 

1. What is an nth degree polynomial?

An nth degree polynomial is a mathematical expression that contains a variable raised to the power of n, where n is a non-negative integer. The highest power of the variable in the polynomial is known as the degree of the polynomial.

2. What is the sum of an nth degree polynomial?

The sum of an nth degree polynomial is the result of adding all the terms of the polynomial. This is achieved by combining like terms, which means simplifying terms that have the same variable and exponent. The sum of an nth degree polynomial can also be represented as a polynomial of the same degree.

3. What is the product of an nth degree polynomial?

The product of an nth degree polynomial is the result of multiplying all the terms of the polynomial. This is achieved by using the distributive property of multiplication over addition. The product of an nth degree polynomial can also be represented as a polynomial of degree n + n = 2n.

4. How do you find the sum and product of two nth degree polynomials?

To find the sum of two nth degree polynomials, combine like terms and simplify the resulting polynomial. To find the product of two nth degree polynomials, use the distributive property of multiplication to multiply each term of one polynomial by each term of the other polynomial, and then combine like terms and simplify the resulting polynomial.

5. What are some real-life applications of nth degree polynomials?

Nth degree polynomials can be used to model various real-life phenomena, such as population growth, stock market trends, and projectile motion. They are also commonly used in engineering and physics to represent complex systems and equations.

Similar threads

  • Calculus and Beyond Homework Help
Replies
24
Views
793
  • Calculus and Beyond Homework Help
Replies
1
Views
1K
  • Calculus and Beyond Homework Help
Replies
6
Views
2K
  • Calculus and Beyond Homework Help
Replies
2
Views
857
  • Calculus and Beyond Homework Help
Replies
3
Views
1K
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
13
Views
2K
  • Calculus and Beyond Homework Help
Replies
12
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
1K
Back
Top