Row Definition and 220 Threads

  1. N

    I In 4x4 matrix when does row swapping not affect eigenvaluess?

    The title pretty much says it... I know that in general eigenvalues are not necessarily preserved when matrix rows or columns are swapped. But in many cases it seems they are, at least with 4x4 matrices. So is there some specific rule that says when eigenvalues are preserved if I swap two rows...
  2. durandal

    Engineering The Telegraph Equation

    I have tried row reduction to solve for the first eigenvector but I don't feel like I get any closer to the solution:
  3. R

    B Row reduction, Gaussian Elimination on augmented matrix

    Hi! Please, could you help me on how to solve the following matrix ? I need to replace the value 3 on the third line by 0, the first column need to remain zero and 1 for the third column. I'm having a lot of difficulties with this. How would you proceed ? Thank you for your time and help...
  4. entropy1

    B How to multiply matrix with row vector?

    How do I calculate a 3x3 matrix multiplication with a 3 column row vector, like below? ## \begin{bmatrix} A11 & A12 & A13\\ A21 & A22 & A23\\ A31 & A32 & A33 \end{bmatrix}\begin{bmatrix} B1 & B2 & B3 \end{bmatrix} ##
  5. C

    I Factoring Matrices with Elementary Row Operations

    Dear Everybody, I have some trouble with this problem: Finding a sequence of elementary matrix for this matrix A. Let ##A=\begin{bmatrix} 4 & -1 \\ 3& -1\end{bmatrix}##. I first used the ##\frac{1}{4}R1##-> ##R1##. So the ##E_1=\begin{bmatrix} \frac{1}{4} & 0 \\ 0& 1\end{bmatrix}##. So the...
  6. M

    MHB Row echelon form : Can the first column contain only zeros?

    Hey! :giggle: Let \begin{equation*}A=\begin{pmatrix}0 & -2 & 2 & 0 & 0 & -6 \\ 0 & 0 & 0 & 1 & 1 & 3\\ 0 & 0 & 0 & 1 & -1 & -1 \\ 0 & 1 & -1 & 0 & 2 & 7\\ 0 & 3 & -3 & 1 & 2 & 14\end{pmatrix}, \ b_1=\begin{pmatrix}0 \\ 0 \\ 0 \\ 0 \\ 0\end{pmatrix} , \ b_2=\begin{pmatrix}-2 \\ 1 \\ -1 \\ 3 \\...
  7. R

    MHB How Can I Transform This Matrix Using Elementary Operations?

    I am stuck on this problem and keep going in a cycle coming back to the same state and would like to get hints on how to proceed. \( A \) is a \(R^{m*n} \) matrix and \( B \) is a \( R^{n*p} \) matrix. \( I_{n} \) is the \( n*n \) identity matrix. Use elementary row and column operations to...
  8. karush

    MHB 307.1.1 Use row reduction on the appropriate augmented

    $\tiny{307.1.1}$ Use row reduction on the appropriate augmented matrix to solve the following system of equations: $\begin{array}{ll}3x+2y&=2\\x-y&=1\end{array} \sim\left[\begin{array}{rr|r}3&2&2\\ \:1&-1&1\end{array}\right]\sim \begin{bmatrix}1&0&\frac{4}{5}\\ 0&1&-\frac{1}{5}\end{bmatrix}$...
  9. karush

    MHB Complete augmented by row operations

    $\left[ \begin{array}{rrrr|r} 1& -5& 4& 0&0\\ 0& 1& 0& 1&0\\ 0& 0& 3& 0&0\\ 0& 0& 0& 2&0 \end{array}\right] $ OK my first move on this is $r_3/3$ and $r_4/2$. $\left[ \begin{array}{rrrr|r} 1& -5& 4& 0&0\\ 0& 1& 0& 1&0\\ 0& 0& 1& 0&0\\ 0& 0& 0& 1&0 \end{array}\right]$ $r_2-r_4=r_2\quad$ doesn't...
  10. M

    MHB Define matrix to get a row operation of type 1

    Hey! :o We have the matrices \begin{equation*}a=\begin{pmatrix}1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9\end{pmatrix}, \ \ E_{1,3}=\begin{pmatrix}0 & 0 & 1 \\ 0 & 0 & 0 \\ 0 & 0 & 0\end{pmatrix}, \ \ u_n=\begin{pmatrix}1 & 0 & 0 \\ 0 & 1 & 0 \\ 0 &0 & 1\end{pmatrix}\end{equation*} I have...
  11. karush

    MHB 5.3 Show that a square matrix with a zero row is not invertible.

    Show that a square matrix with a zero row is not invertible. first a matrix has to be a square to be invertable if $$\det \begin{pmatrix}1&0&0\\ 0&1&0\\ 3&0&1\end{pmatrix}=1$$ then $$\begin{pmatrix} 1&0&0\\ 0&1&0\\ 3&0&1\end{pmatrix}^{-1} =\begin{pmatrix}1&0&0\\ 0&1&0\\ -3&0&1...
  12. R

    MHB Calculating Probability of Choosing 11 Reds in a Row

    I realize this is probably quite easy and basic but I just can't get comfortable with calculators to work it our with any certainty. There are 100 socks in a drawer. 84 are Red. 16 are White. If you are blindfolded & have to choose 11 socks randomly, what is the odds or what it more likely...
  13. A

    B Finding Bases for Row and Column Spaces

    I'm doing problems on finding row and column spaces. My textbook tells me to find the echelon form of the matrix, and then to identify the bases. My question is, can I reduce the matrix to reduced echelon form to get the bases? I have the same question about bases for the solution space.
  14. A

    The expected value for 7 heads in a row

    Homework Statement We have a coin with probability ##0\leqslant p \leqslant 1## of getting heads. We flip the coin until we get ##7## heads in a row. Let ##N_7## be the number of necessary flips to get the ##7## heads in a row. What is the expected value ##E(N_7)##? Homework Equations The...
  15. C

    MHB Row reduced echelon form and its meaning

    Hey. I have the following question to solve: * Given a matrix A that is size m x n and m>n. Let R be the RREF that we get by Gaussian elimination of A. Prove that the system equation Ax=0 has only one solution iff in every column of R there is a leading element. I have some answer of...
  16. M

    How to plot timestamps within a row?

    i have a dataset that has the timestamp data within each row and I am trying to plot the values to see the distribution but have no idea how to do it if the data is presented this way as attached. any ideas? thanks
  17. B

    Create Row-Orthonormal Matrix | m > n

    Hello, I'm looking for a way to create an approximate row-orthonormal matrix with the number of rows (m) > the number of columns (n); i.e., finding A(mxn) so that A(mxn) . A^T(nxm) = I(mxm). I used singular value decomposition (e.g., DGESVD in mkl mathlib), but what I actually got was an...
  18. karush

    MHB Find determinant by row reduction in echelon

    $\textsf{a. Find the determinants by row reduction in echelon form.}$ $$\left| \begin{array}{rrr} 1&5&-6\\ -1&-4&4 \\ -2&-7 & 9 \end{array} \right|$$ ok i multiplied $r_1$ by 1 and added it to $r_2$ to get $$\left| \begin{array}{rrr} 1&5&-6\\ 0&1&-2 \\ -2&-7 & 9 \end{array} \right|$$...
  19. O

    MHB How does the row picture differ from the column picture in linear systems?

    Hi, I hope someone can help. I'm wanting to get a better grasp on the connection between the row picture v.s. the column picture of linear systems and their solutions. In the picture below, the row picture are the three graphs on the top and their corresponding column pictures are below them...
  20. B

    B Proof of elementary row matrix operation.

    Prove that interchange of two rows of a matrix can be accomplished by a finite sequence of elemenatary row operations of the other two types. My proof :- If ##A_k## is to be interchanged by ##A_l## then, ##\displaystyle \begin{align} A_k &\to A_l + A_k \\ A_l &\to - A_l \\ A_l &\to A_k + A_l...
  21. T

    MHB Probability of event given another event occurs twice in a row

    I have $P(B) = 0.4$ and $P(\lnot B) = 0.6$. $P(TS|B) = 0.7$ and $P(TS|\lnot B) = 0.25$ $P(B|TS) = 0.65116$ and $P(\lnot B|TS) = 0.34884$ (from bayes theorem). Now, if we get $B$ or $\lnot B$, and we get the same event twice in a row so we get $B$ then $B$ or $\lnot B$ then $\lnot B$, what...
  22. L

    I What is the Basis for the Null Space in Matrix A?

    Hello there. I'm currently trying to come to terms with the aforementioned topics. As I am self studying, a full understanding of these concepts escapes me. There's something I'm not grasping here and I would like to discuss these to clear away the clouds. As I understand it, a basis for some...
  23. SSequence

    Row Shuffling and Permutation Question

    The question below could also be re-phrased in terms of functions of one variable (using indexes). However, it seems it is easier to explain it with two variables. Here is the question: Suppose we have some total recursive function f: N x N→N. Define the n-th row of f as the function Fn : N→N...
  24. W

    Show: Elementary row operations don't affect solution sets

    Homework Statement Show that elementary row operations don't affect solutions sets in linear systems Homework Equations - The Attempt at a Solution It's pretty easy to come up with a random linear system and perform ERO on them and showing that solutions are not affected, but is there all...
  25. S

    First Row BDE's: Why is H-NH2 lower than H-CH3?

    Here are some first row BDE's (in kcal/mol): H-CH3 = 105 <---> [H]+ [CH3]- H-NH2 = 103 H-OH = 119 H-F = 136 <---> [H]+ [F]- This trend is often rationalized in terms of increasing ionic character (or with no-bond resonance). However, the H-NH2 BDE should have a higher ionic contribution than...
  26. G

    Row space of a transformation matrix

    Homework Statement We're given some linear transformations, and asked what the null space, column space and row space of the matrix representations tell us Homework EquationsThe Attempt at a Solution I know what information the column space and null space contain, but what does the row space of...
  27. M

    I Linear least-squares method and row multiplication of matrix

    Suppose that I have an overdetermined equation system in matrix form: Ax = b Where x and b are column vectors, and A has the same number of rows as b, and x has less rows than both. The least-squares method could be used here to obtain the best possible approximative solution. Let's call this...
  28. S

    Determinant of a 3x3 matrix via row reduction

    Homework Statement Show that the determinant of is (a-b)(b-c)(c-a) Homework Equations Row reduction, determinants The Attempt at a Solution Apparently I got a (a-b)^2 instead of (a-b) when I multiplied them up. It would be grateful if someone can point me out where the mistakes are.
  29. arpon

    I Are the columns space and row space same for idempotent matrix?

    Suppose, ##A## is an idempotent matrix, i.e, ##A^2=A##. For idempotent matrix, the eigenvalues are ##1## and ##0##. Here, the eigenspace corresponding to eigenvalue ##1## is the column space, and the eigenspace corresponding to eigenvalue ##0## is the null space. But eigenspaces for distinct...
  30. T

    Linear Algebra, forcing a row exchange.

    the answer key said d is supposed to be 10. but there's a way to evade that row exchange. 1st picture is the question and the 2nd picture is the elimination steps.
  31. K

    Spring System in a Tower: Analysis and Calculations

    Homework Statement [/B] In a tower a princess throws a ladder of 20 plates of thickness d and mass m each, which are connected with springs of constant k and loose length l0. the window is at height H. 1) What's the elongation of each of the spring pairs? 2) What's the total ladder's length. 3)...
  32. A

    Multiplying row exchange matrices

    Homework Statement Multiply these row excahnge matrices in the order pq qp and p^2 p = [0 1 0] [1 0 0] [0 0 1] q= [0 0 1] [0 1 0] [1 0 0] Homework EquationsThe Attempt at a Solution I don't understand why the solution is [0 1 0] [0 0 1] [1 0 0] do you not multiply rows by columns? When i...
  33. Pull and Twist

    MHB Are These Row Equivalent Matrices? Why Am I Getting Different Results?

    I am having trouble with the following problem; a.) Find a matrix B in reduced echelon form such that B is row equivalent to the given matrix A. A=\left[\begin{array}{c}1 & 2 & 3 & -1 \\ 3 & 5 & 8 & -2 \\ 1 & 1 & 2 & 0 \end{array}\right] So using my calculator I am able to get...
  34. kostoglotov

    Row and null complements of x; need clarity....

    I've managed to distill the rambling into just this question, posted here and at the end of my digressive thoughts as well: "Will we always be able to split x up in such a way that we have a nullspace component and a non-row space component?" Take a matrix A = \begin{bmatrix}1 & 2\\ 3 &...
  35. kostoglotov

    Is this the correct way to compute the row echelon form?

    This is actually a pretty simple thing, but the ref(A) that I compute on paper is different from the ref(A) that my TI-89 gives me. Compute ref(A) where A = \begin{bmatrix} 1 & 2\\ 3 & 8 \end{bmatrix} \\ \begin{bmatrix}1 & 2\\ 3 & 8\end{bmatrix} \ r_2 \rightarrow r_2 - 3 \times r_1 \\ \\...
  36. C

    Solving Row Echelon Form: Practicing Tips for Students

    For some reason I just can't seem to wrap my head around the idea of reducing a Matrix to row echelon form. I'm familiar with the steps that the textbooks and tutorials use and how it's done but when I try practicing on my own I feel lost. e.g. all I end up with are just a bunch of random...
  37. P

    How does corrosion affect the resistivity of copper wire?

    I'm not sure if corrosion does have a significant effect on copper in general but if it does, how and why does it happen, and the process of it happening and its effect on the overall resistivity? This is for a physics assignment...Please help if you can. Thank you
  38. L

    Linear Algebra: use elem. row ops to convert A into B

    Homework Statement Show that the given matrices are row equivalent and find a sequence of elementary row ops that will convert A into B. a = 2 0 -1 1 1 0 -1 1 1 b = 3 1 -1 3 5 1 2 2 0 Homework EquationsThe...
  39. PsychonautQQ

    Question about row space basis and Column space basis

    Say a subspace S of R^3 is spanned by a basis = <(-1,2,5),(3,0,3),(5,1,8)> By putting these vectors into a matrix and reducing it to rref, a basis for the row space can be found as <(1,-2,-5),(0,1,3)>. Furthermore, the book goes on to say that this basis spans the subspace S. Cool, not...
  40. M

    Do Row Operations Maintain Equivalence in Matrix Subtraction?

    If you have two arbitrary matrices, A and B, I was wondering if row operations can be performed in any order to produce the same results. For example, you perform elementary row operations on A to produce A', then do A' - B, then also produce a new matrix through elementary row operations on...
  41. PsychonautQQ

    Row and Column equivalent matrices

    Hey PF, I'm having trouble seeing the bigger picture here. Take matrix A and matrix B. If B can be obtained from A by elementary row operations then the two matrices are row equivalent. The only explanation my book gives is that since B was obtained by elementary row operations, (scalar...
  42. morrobay

    Color Permutations In Row Of 6 Red, 3 Blue, 3 Green Flower Pots ?

    With 6 red, 3 blue and 3 green flower pots, how many color permutations in row of 12 are there ? Its not 12! or n!/(n-r)!
  43. Z

    3 in a row probability problem

    What would the probability be of 10 randomly generated numbers producing exactly 3 0s in a row at any point in the 10 entries? Ex: 1. 5 2. 0 3. 0 4. 0 5. 9 6. 8 7. 1 8. 0 9. 8 10. 2 Using a binomial distribution to find the probability of any 3 out of 10 I got: 1/10 chance of...
  44. Y

    Row Reduction to solve for 6 Unknowns

    Homework Statement I am in a calculus class where we are learning the introduction to row reduction. I have done this before in other courses, so I am familiar with the process, but I am not sure about this one. We were given: x4 + 2x5- x6 = 2 x1 + 2x2 + x5 -x6 = 0 x1 + 2x2 + 2x3 - x5 +...
  45. U

    Arranging Persons in a Row with Constraints

    Homework Statement The number of ways in which 4 persons P1,P2,P3,P4 can be arranged in a row such that P2 does not follow P1, P3 does not follow P2 and P4 does not follow P3 is The Attempt at a Solution Let us assume that P1 occupies the first position. So, the next position can be...
  46. davenn

    2 x M 6.8 quakes 2 days in a row

    hi guys as per title Yesterday, 10 March 2014 there was a M 6.8 offshore of northern California in the Mendocino Fracture Zone of the Juan De Fuca Plate Just coming in on the seismo right now is another M 6.8, east of the South Sandwich Islands right at the southern end of the Atlantic Ocean...
  47. Quarlep

    Differences between row and column vectors

    I want to show a vector in matrix but I didnt uderstand differentes between row matrix and column matrix Let's suppose I have a 2i+3j How I will show this vector in matrix ? I will use a row matrix or column matrix.
  48. Y

    How Can I Determine the Number of Solutions in a Dependent System?

    Homework Statement Write and row reduce the augmented matrix to find out whether the given set of equations has exactly one solution, no solutions, or infinitely many solutions. -x+y-z=4 x-y+2z=3 2x-2y+4z=6 Homework Equations The Attempt at a Solution I saw right away that...
  49. F

    MHB If a row is added to any matrix is it still the same matrix?

    Is it correct to say it doesn't matter if a row of zeros is added on to a matrix? For example does \begin{bmatrix}1&2\\3&4 \end{bmatrix} = \begin{bmatrix}1&2\\3&4 \\ 0&0 \end{bmatrix} Does it depend on context? For example if the matrix is representing a linear system of equations then this...
  50. T

    Odds of Losing 50 Coin Flips in a Row: Calculations & Betting

    If your betting on a coin flip but person a is the banker and person b can quit at any time, does person b have an advantage. The martingale theory of doubling a losing bet doesn't work if there is a maximum bet. Start at 5 and going to the max of 1000 a person can bet...
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