Polynomials Definition and 740 Threads

  1. C

    Mastering Factoring Polynomials: Tips, Tricks, and Examples to Help You Succeed!

    Alright, I'll be honest. I was extremely tired and slept all through the lesson in Algebra today lol. And now I need help with factoring polynomials. Example problems that I need help on: 7h3+448 Perfect square factoring - y4-81 Grouping - 3n3-10n2-48n+160 You don't have to answer...
  2. M

    What Are the Rank and Nullity of a Linear Transformation?

    Homework Statement find the rank and nullity of the linear transformation T:U -> V and find the basis of the kernel and the image of T Homework Equations U=R[x]<=5 V=R[x]<=5 (polynomials of degree at most 5 over R), T(f)=f'''' (4th derivative) The Attempt at a Solution Rank = 2...
  3. S

    Finding g(t) for Characteristic Polynomial f(t) = t2 - 5t + 4 and Matrix A

    Homework Statement Suppose A is a 2x2 real matrix with characteristic polynomial f(t) = t2 - 5t +4. Find a real polynomial g(t) of degree 1 such that (g(A))2 = A. Suppose A is a 2x2 complex matrix with A2 ≠ O. Show that there is a complex polynomial g(t) of degree 1 such that (g(A))2 = A...
  4. Y

    Question on Rodrigues' equation in Legendre polynomials.

    I have problem understand in one step of deriving the Legendre polymonial formula. We start with: P_n (x)=\frac{1}{2^n } \sum ^M_{m=0} (-1)^m \frac{2n-2m)}{m!(n-m)(n-2m)}x^n-2m Where M=n/2 for n=even and M=(n-1)/2 for n=odd. For 0<=m<=M \Rightarrow \frac{d^n}{dx^n}x^2n-2m =...
  5. L

    Dividing Polynomials With Exponents

    Nevermind Solved it.
  6. K

    MATLAB Integrating and Differentiating Polynomials in MATLAB

    Hello, First of all, I am not trying to "spam" subforums. I found out that my thread shouldn't be posted under homework. Anyways, here it is. Integration Let say there's a polynomial, 5x+6 and you want to integrate from 0 to 3 respect to x, how do you input in MATLAB? (I guess you can't...
  7. K

    Linear algebra - matrices and polynomials

    Homework Statement Prove for each square matrix B there is a real polynomial p(x) (not the zero polynomial) so p(B)=0 Homework Equations Rank-nullity? dimv = r(T) + n(T) The Attempt at a Solution I've found the dimension for nxn square matrices (n²) and a basis (1 in one place and...
  8. J

    Cubic Polynomials: Solving w/o Rational Roots

    Homework Statement I think I saw another thread answer this question, but I was a little lost whilst reading it. I have just recently learned of the rational root theorem and was using it quite happily; figuring out what possibly answers went with cubic and quartic polynomials gave new...
  9. N

    Calculating Residues of Reciprocal Polynomials

    I have need to calculate the residues of some functions of the form \frac{f(x)}{p(x)} where p(x) is a polynomial. To be more specific I have already calculated the 2 residues of \frac{1}{x^2+a^2}. That one was quite easy. Now I'm asked to calculate the residues of...
  10. Z

    A question about zeros of polynomials

    POlynomials (or Taylor series ) of the form P(x)= \sum_{n}a_{2n}X^{2n} with a_{2n}\ge 0 strictly have ALWAYS pure imaginary roots ?? it happens with sinh(x)/x cos(x) could someone provide a counterexample ? is there an hypothesis with this name ??
  11. F

    Integrating legendre polynomials with weighting function

    Homework Statement I recently came across this integral while doing a problem in electromagnetism (I'm not sure if there exists a nice analytic answer): \int_{0}^{\pi}P_m(\cos(t))P_n(\cos(t)) \sin^2(t) = \int_{-1}^{1}P_m(x) P_n(x) \sqrt{1-x^2}, Homework Equations P_m(x) is the m^th...
  12. G

    Prove Lagrange Polynomials Basis of $\mathbb{R}_{n}[X]

    hello everyone:smile: for i=1,2,...,(n+1) let P_{i}(X)=\frac{\prod_{1\leq j\leq n+1,j\neq i}(X-a_j)}{\prod_{1\leq j\leq n+1,j\neq i}(a_i-a_j)} prove that (P_1,P_2,...P_{n+1}) is basis of \mathbb{R}_{n}[X] . i already have an answer but i don't understand some of it. ... we have...
  13. B

    A subspace spanned by polynomials 1 and x

    1. Let W be the linear subspace spanned by the polynomials 1 and x. Find an orthogonal projection of the polynomial p(x) = 1+x^2 to W. Find a basis in the space W(perp) My problem is that I don't know how to represent W as a matrix so that I could apply the orthogonal projection formula...
  14. O

    Why is simpsons rule exact for 3rd degree polynomials?

    this is really perplexing. how can it be exact? simpsons rule uses quadratics to approximate the curve. how can it be exact if I am approximating a cubic with a quadratic?
  15. E

    Polynomials f(x) & g(x) in Z[x] Relatively Prime in Q[x]

    trying to show that polynomials f(x), g(x) in Z[x] are relatively prime in Q[x] iff the ideal they generate in Z[x] contains an integer.Thanks .Not homework
  16. B

    Solving complex exponential polynomials

    Are there any general methods to solve the following complex exponential polynomial without relying on numerical methods? I want to find all possible solutions, not just a single solution. e^(j*m*\theta1) + e^(j*m*\theta2)+e^(j*m*\theta3) + e^(j*m*\theta4) + e^(j*m*\theta5) = 0 where...
  17. N

    Are Ho(x) and H1(x) orthogonal to H2(x) with respect to e^(-x^2)?

    In my third year math class we were asked a question to prove that Ho(X) and H1(x) are orthogonal to H2(x), with respect to the weight function e^(-x^2) over the interval negative to positive infinity where Ho(x) = 1 H1(x) = 2x H2(x) = (4x^2) - 2 i know that i have to multiply Ho(x) by...
  18. G

    Inner Product of Polynomials: f(x) & g(x)

    Homework Statement Define the inner product of two polynomials, f(x) and g(x) to be < f | g > = ∫-11 dx f(x) g(x) Let f(x) = 3 - x +4 x2. Determine the inner products, < f | f1 >, < f | f2 > and < f | f3 >, where f1(x) = 1/2 , f2(x) = 3x/2 and f3(x) = 5(1 - 3 x2)/4 Expressed as a...
  19. T

    Subspace of Polynomials of degree 2

    I'm trying to show that a set W of polynomials in P2 such that p(1)=0 is a subspace of P2. Then find a basis for W and dim(W). I have already found that the set W is a subspace of P2 because it is closed under addition and scalar multiplication and have showed that. The thing I'm stuck on...
  20. Z

    Do Orthogonal Polynomials have always real zeros ?

    Do Orthogonal Polynomials have always real zeros ?? the idea is , do orthogonal polynomials p_{n} (x) have always REAl zeros ? for example n=2 there is a second order polynomial with 2 real zeros if we consider that there is a self-adjoint operator L so L[p_{n} (x)]= \mu _{n} p_{n} (x)...
  21. A

    How Long Does It Take for a Bullet Fired Upward to Fall Back Down?

    this seems more like a physics word problem, I am not even sure how to set this problem up to use it as a polynomial. "A person holds a pistol straight upward and fires. The initial velocity of most bullets is around 1200 ft/sec. The hieght of the bullet is a function of time and is...
  22. A

    How Do You Solve Complex Polynomial Long Division Problems?

    Divide the polynomials by using long division. (-9x^6+7x^4-2x^3+5)/(3x^4-2x+1) When I attempted it I started by pulling using 3x^2 . multiplied that by the (3x^4-2x+1) and from there I had to use a fraction of 7/3 or something and then couldn't divide into x cubed. If anyone can...
  23. N

    Finding Taylor Polynomials and Error for f(x)=3x+cos(3x) about X0=0

    Homework Statement Find the Taylor Polynomial T2(x) (degree 2) for f(x) expanded about X0. f(x)=3x + cos(3x) X0= 0 Find the error formula and then find the actual (absolute) error using T2(0.6) to approx. f(0.6). The Attempt at a Solution As I've said on this forum before...
  24. M

    Subspace of polynomials, find basis

    Trying to solve a question in linear algebra. P2 is a polynomial space with degree 2. Is P(t): P'(1)=P(2) (P' is the derivative) a subspace of P2. What is the basis ? It seems that it is a subspace with basis 1-t,2-t2. Can anybody explain how this can be found?
  25. N

    The set of 4-degree polynomials (Linear algebra)

    Homework Statement If P is the set of all 4-degree polynomials, and W is the subset of all 4-degree polynomials such that p(-2) = p(2), find a set S such that W = span(S). Homework Equations The Attempt at a Solution My guess is that one set that works is x^4, x^2, and 1. My...
  26. M

    Taking legendre polynomials outside the integral in a multipole expansion

    Homework Statement A chare +Q is distributed uniformly along the z axis from z=-a to z=+a. Find the multipole expansion. Homework Equations Here rho has been changed to lambda, which is just Q/2a and d^3r to dz. The Attempt at a Solution I have solved the problem correctly...
  27. J

    Simplifying Polynomial Fractions

    Homework Statement I need to simplify this: ((84/13)x4y - 4) / (-x + (21/13)x5)y)Homework Equations The Attempt at a Solution I don't know if it can be simplified further. I can't factor anything out that will cancel. I multiplied both the top and the bottom by 13 to get rid of those fractions...
  28. U

    Why Is \( n^3 - n \) Always Divisible by 3?

    Polynomials divisible by... Homework Statement 1) Explain why n^3 - n is always divisible by 3 for any n that is an element of the natural numbers. 2) Give 2 other polynomials that are always divisble by 3. 3) Give 2 polynomials that are divisible by 2 but not 4, and 2 other polynomials...
  29. H

    Divisibility of Polynomials: Finding the Remainder

    Homework Statement A polynomial p(x) leaves the rest 3 when divided by (x+2) and the rest 8 when divided by (x-6). What's the rest r(x) when p(x) is divided by (x+2)(x-6)? Homework Equations The Attempt at a Solution I wrote the three equations: p(x)=q1(x+2) + 3 p(x)=q2(x-6) +...
  30. R

    How Can You Factorize the Polynomial \( x^6 - 1 \)?

    Homework Statement Consider the polynomial p(x)=x^6-1. (Apply over any field F). (a) Find two elements a,b \in F so that p(a)=p(b)=0. Then use your answer to find two linear factors of p(x). (b) Show that the other factor of p(x) is x^4+x^2+1 (c) Verify the identity...
  31. Somefantastik

    MATLAB Is There a MATLAB Routine for Simple Legendre Polynomials of a Specific Degree?

    I see in MATLAB that you can call legendre(n,X) and it returns the associated legendre polynomials. All I need is is the simple Legendre polynomial of degrees 0-299, which corresponds to the first element in the array that this function returns. I don't want to call this function and get this...
  32. M

    Solutions to a set of polynomials (Commutative Algebra)

    Hi I have a set of nonlinear equations f_i(x_1,x_2,x_3...) and I want to find their solutions. After doing some reading I have come across commutative algebra. So to simplify my problem I have converted my nonlinear equations into a set of polynomials p_i(x_1,x_2,x_3...,y_1,y_2...) by...
  33. W

    Problem on space of polynomials in two variables, is there something wrong ?

    Homework Statement Let P(n,m) be the space of all polynomials z with complex coefficients, in two variables s and t, such that either z = 0 or else the degree of z(s, t) is <= m - 1 for each fixed s and <= n - 1 for each fixed t. Prove that there exists an isomorphism between Pn (x)...
  34. P

    Permutations of Subscripts for Unchanged Value in Polynomial Symmetry

    Homework Statement (x_1 - x_2)(x_3 - x_4) Find permutations of subscripts that leave value unchanged Homework Equations The Attempt at a Solution Okay so I know that it's asking how I should rearrange things and still not change the value. Switching 1 with 2 or 3 with 4 would work but I know...
  35. B

    How can specific values be constructed in polynomials with given roots?

    There's a question in Calculus by Spivak about polynomials and I was wondering about how to construct them to have specific roots or values at certain points. For example it says if x_{1}, ..., x_{n} are distinct numbers, find a polynomial f_{i} such that it's of degree n-1 which is 1 at x_{i}...
  36. L

    What is the Probability of Factoring Random Monic Polynomials?

    I've been trying to work out a bunch of problems that have to do with finding irreducible polynomials, and this one really seemed to stump me... What is the probability that a random monic polynomial over F_3 of degree exactly 10 factors into a product of polynomials of degree less than or...
  37. P

    Greatest common divisor of polynomials

    HI there, I have a tiny question concerning the gcd of polynomials. Assume, \chi is the greatest common divisor of the polynomails p_{ij}, i,j=1,2. I then form q_{11}=p_{11}^2+p_{12}^2,\quadd q_{12}=p_{11}p_{21}+p_{12}p_{22},\quadd q_{21}=p_{21}p_{11}+p_{22}p_{12},\quadd...
  38. M

    Very Interesting Question on Division of Polynomials

    Very Interesting Question on Division of Polynomials! [b]1. Question: 'When a polynomial f(x)= x^4 - 6x^3 + 16x^2 - 25x + 10 is divided by another polynomiall g(x)= x^2 - 2x + k, the remainder is x+a. Find the value of a k and a'. Homework Equations [b]3. I tried solving it by...
  39. E

    Equal Coefficients Polynomials

    Here is something that always bugged me, and I think I have an explanation for it now, but I am wondering if it is correct. Alright, the problem to me was that back when I was in Diff-eq, to use undetermined coefficients with polynomials, we would always group together the terms on one side, and...
  40. K

    A problem of charateristic polynomials' divisibility

    Homework Statement A is a square matrix of size n, B is of size m, C is an m*n(typo,should be n*m) matrix and n>m ,Rank(C)=m. if AC=CB, prove characteristic polynomial of B divides that of A. Homework Equations nothingThe Attempt at a Solution I think I need to prove any eigenvalue of B is an...
  41. D

    Is this set of polynomials a subspace of P2?

    Homework Statement Let S denote the collection of all polynomials of the form p(t) = (2a - b)t^2 + 3(c - b)t + (a - c), where a,b,c are real numbers. Determine whether or not S is a subspace of P2. The Attempt at a Solution Okay, so I know that in order for S to be a subspace, it must...
  42. J

    Explaining How Ring of Polynomials Not Having Inverses Impacts Matrix Entries

    Question: Can someone explain the following to me: "... the entries of the matrix A - tI_n are not scalars in the field F. They are, however, scalars in another field F(t), the field of quotients of polynomials in t with coefficients from F." I asked someone earlier today, and I got an...
  43. M

    Linear Transformations using polynomials

    Homework Statement Let P3 be the space of all polynomials (with real coefficients) of degree at most 3. Let D : P3 -> P3 be the linear transformation given by taking the derivative of a polynomial. That is D(a + bx + cx2 + dx3) = b + 2cx + 3dx2: Let B be the standard basis {1; x; x2; x3}...
  44. V

    Finding Roots of Polynomials in C

    Homework Statement Show the the equation f(z) = z^4 + iz^2 + 2 = 0 has two roots with |z|=1 and two roots with |z|=sqrt(2), without actually solving the equation.Homework Equations Rouche's theorem, the argument principle?The Attempt at a Solution This is what I have done so far: First show...
  45. stringy

    Complex Polynomials: Proof of Complex Root Existence

    Hello, I'm working through Polynomials by Barbeau. I think I may have provided a decent proof for one of the exercises, but I'd like a second opinion. Here's the exercise: Show that every quadratic equation with complex coefficients has at least one complex root, and therefore can be written...
  46. P

    Determining Irreducibility of f(x) and Third Degree Polynomials in Q[x]

    Please somebody help me with this it is very urgent. I have that f(x) = x^5-5x+1 has S_5 as galois group over rationals. ANd M is the splitting field of f(x) over rationals. Then how can I show that : determine f(x) is irreducible over Q({-51}^{1/2})[x] or not? Determine if there is...
  47. B

    Determining Legendre polynomials (Boas)

    I am having trouble evaluating the Legendre Polynomials (LPs). I can do it by Rodrigues' formula but I am trying to understand how they come about. Basically I have been reading Mary L. Boas' Mathematical Methods in the Physical Sciences, 3E. Ch.12 §2 Legendre Polynomials pg566. In the...
  48. X

    Characteristic Polynomials and Minimal polynomials

    Hi, there are a few questions and concepts I am struggling with. The first question comes in 3 parts. The second question is a proof. Question 1: Please Click on the link below :smile: Question 2: Please Click on the link below :smile: For Q2, could you please show me how to...
  49. D

    Finding Polynomials with Integer Coefficients & \sqrt(2) + i Zero

    Homework Statement Find a polynomial with integer coefficient for which \sqrt(2) + i is a zero. Homework Equations The Attempt at a Solution I'm not sure where to really start with this one. It is on my review sheet, and I can't remember how to do it. Could someone give me a hand?
  50. J

    Proof of Taylor's formula for polynomials

    My book reads as follows: "This is an entirely elementary algebraic formula concerning a polynomial in x or order n, say f(x) = a_0 + a_1x + a_2x^2 + ... + a_nx^n . If we replace x by a + h = b and expand each term in powers of h, there results immediately a representation of the form...
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