Multiplication Definition and 496 Threads

  1. T

    B Number of concepts of Multiplication and Addition

    Hi,can someone exaplain me,why do we have a few concepts of multiplication,like repeated addition,scaling,grouping etc...but only one concept for addition that means to put something together and make it more or bigger I was solving in past,why multipliplication produce new unit and so on...but...
  2. D

    Linear Algebra Book about block matrix multiplication

    I still can't find a book with properties and theorems involving block matrices multiplication to reference in my undergraduate work. thanks
  3. D

    Master Matrix Multiplication: Solving Size Confusion | Homework Help

    Homework Statement Well, basically my issue isn't exactly with how to multiply matrices. I know how to do that, my issue is the way my lecturer shows how to find the size of the new matrix, this is all that he shows: I mean how is he getting AX to be a 3x1 matrix? Homework EquationsThe...
  4. M

    How to calculate the foraging radius of a bird?

    I would love someone to verify the answer for equation 8 in this paper (bottom of page 263) http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2028.2002.00368.x/epdf For the sake of clarity here is the equation is LaTeX which you can render at the following link \frac{QC + Q\lambda \sigma -...
  5. PhysicsBoyMan

    Understanding Exponent Multiplication: cnxn-1

    Homework Statement x(cnxn-1) 3. The Attempt at a Solution I know that the answer is cnxn I'm not sure why though. My thinking is that we have cnxn-1 and we multiply that by x. x times x is x2 so I'm expecting a 2 to interact with the n-1 in the exponents. I'm just not sure how n-1 interacts...
  6. T

    MHB Problem with cross multiplication

    Hello, I have been poring over this problem for days, and I would really appreciate some help. I'm not sure if it's an algebra problem exactly. It's from my physiology class. The professor said it's simple cross multiplication, and I asked him to explain it again, but I didn't understand his...
  7. S

    Lie group multiplication and Lie algebra commutation

    I've heard it said that the commutation relations of the generators of a Lie algebra determine the multiplication laws of the Lie group elements. I would like to prove this statement for ##SO(3)##. I know that the commutation relations are ##[J_{i},J_{j}]=i\epsilon_{ijk}J_{k}##. Can you...
  8. S

    Understanding the physical meaning of multiplication, etc

    Is there some kind of intuitive way to understand the physical meaning when mathematical operations are applied to equations in physics? What I mean is that, say we start with a 'starting point' equation, in this example Ficks law of diffusion (wikipedia:): J = -D \frac{\delta \phi}{\delta x}...
  9. C

    MHB Create a multiplication table program

    Create a program in C++ that makes a multiplication table. Ask the user how many numbers should be in the table. Requirements Store all of the data in a 2-dimensional vector of ints. Allow the program to run repeatedly until the user is finished. Do not allow inputs outside the range of 1-9...
  10. J

    Do similar matrices respect multiplication

    Homework Statement Let ##G=GL_n(F)## for ##F## a field, and define an equivalance relation by ##A\sim B## iff ##A## and ##B## are conjugate, that is, iff ##A=PBP^{-1}## for some ##P\in GL_n(F)##. Does ##\sim## respect multiplication?Homework Equations The equivalency respects multiplication...
  11. Z

    Vector multiplication in static equilibrium

    Homework Statement A 1 200-N uniform boom at 65 degrees to the vertical is supported by a cable at an angle of 25 degrees to the horizontal . The boom is pivoted at the bottom, and an object of weight = 2 000 N hangs from its top. Find the tension in the support cable Homework EquationsThe...
  12. TheMathNoob

    Multiplication rule for conditional probabilities

    Homework Statement Selecting Two Balls. Suppose that two balls are to be selected at random, without replacement, from a box containing r red balls and b blue balls. We shall determine the probability p that the first ball will be red and the second ball will be blue I am confusing Pr(A|B) and...
  13. O

    Is multiplication associative in physics?

    Work = Force X Distance. ? = Distance X Force How do you make sense of the second equation?
  14. H

    Understanding Vector Multiplication

    Hi i am trying to understand this thoroughly Basically i am trying to understand vector multiplication, i don't know if it is the cross product or the dot product i am thinking of Okay so here is the question and what is confusing me in the answer So if we have two vectors and we multiply...
  15. evinda

    MHB Is the Degree of the Product of Two Polynomials 2n?

    Hello! (Wave) For polynomial multiplication, if $A(x)$ and $B(x)$ are polynomials of degree-bound $n$, we say that their product $C(x)$ is a polynomial of degree-bound $2n-1$ such that $C(x)=A(x)B(x)$ for all $x$ in the underlying field. A way to express the product $C(x)$ is $$C(x)=...
  16. SrVishi

    Proving Dedekind cut Multiplication is closed

    Homework Statement I am reading Rudin's Principles of Mathematical Analysis (3rd edition) and am working through the construction of ##\mathbb{R}##. In step 6 of his construction, we must first verify that the field properties of multiplication hold for how he defines multiplication for the...
  17. K

    Why beryllium for neutron multiplication

    I've been going over the cross sections on Sigma, and I'm a little confused as to why beryllium is the most talked about neutron multiplier I've come across. I mean, it does have a few things going for it: multiplication down to lower energy levels than most multipliers, and a very low (n...
  18. Math Amateur

    Multiplication of Path Classes and the Fundamental Group

    In Chapter 7 of John M. Lee's book on topological manifolds, we find the following text on composable paths and the multiplication of path classes, [f] ... ... Lee, writes the following:In the above text, Lee defines composable paths and then defines path multiplication of path classes (not...
  19. Dark_Capacitor

    Why AM wave is multiplication of carrier and message signal?

    Let A= (sin(x) * sin(100x)) + sin(100x).; modulation index is 1; Let B= (sin(x) + sin (100x)); Both of these waves have same frequency and both are amplitude modulated. When passed through an envelope detector, both will give message signal. And B have an advantage of not having any sideband...
  20. A

    Using 3 Vectors to Show Vector Multiplication is Not Commutative

    Homework Statement That is, use three specific vectors in 3-space to show that...
  21. S

    Question in quaternion multiplication

    Hi guys, I am taking this class in lie groups but the professor never introduced the concept of quaternion and he asked about it. I saw from google the properties of multiplications of j and I made the multiplication according to (B + jC)(u + jv) = Bu + Bjv + jCu + j^2Cv = Bu - Cv + j(Cu + Bv)...
  22. evinda

    MHB Proving Properties of Multiplication for Natural Numbers

    Hello! (Wave) For each pair of natural numbers $m \in \omega, n \in \omega$ we define the multiplication between $m,n$ (as a function $\cdot: \omega \times \omega \to \omega $) like that: $$m \cdot 0=0$$ $$m \cdot n'=m \cdot n+m$$ I want to show that for each $m \in \omega, n \in \omega, k...
  23. K

    A Language Spin: The Paradox of Zero Multiplication and Social Perception

    If Anna has 0 coins and Bertus has 0 coins aswell. Can you say that Anna has twice as much coins as Bertus? Because 2*0=0. But couldn`t you also say that Anna has four times more coins than Bertus, but simultaneously Bertus has 5 times more coins than Anna? Making it a paradox?
  24. A

    Understanding Limits: Addition and Multiplication Rules

    (I have posted this in this section, rather than homework, because I hope to improve my general understanding of methods of finding limits through these problems.) 1: \lim_{x\rightarrow0} (\frac{cosec(x)}{x^3} - \frac{sinh(x)}{x^5}) I don't really know what to do with this one. I tried...
  25. D

    Geometry question form ax^2+bx+c

    I was tutoring a student and I came across the following question. I feel like I'm missing something obvious, but it seems like there are too many variables for an answer to be determined. The attached picture contains all of the question details.
  26. M

    MHB Multiplication of two n-bit numbers

    Hey! :o I am looking at the divide-and-conquer technique for the multiplication of two $n-$bit numbers.First of all, why does the traditional method of the multiplication of two $n-$bit numbers require $O(n^2)$ bit operations?? (Wondering) The divide-and-conquer approach is the following: Let...
  27. H

    Proof: Multiplication is commutative

    Homework Statement Let n,m be natural numbers. Then n x m = m x n. Prove this. Homework Equations In order to prove this i am asked to prove 2 Lemma that will be useful. In my solution i will (attempt to) prove these first.Definition of multiplication; for all m in N 0 x m = 0, (n++) x m :=...
  28. K

    Multiplication of an Identity Matrix by a Column

    Homework Statement [/B] This is a seemingly simple problem. All I have to do is multiply two matrices: [ 1 0 ] [ 0 1 ] (A) and [ 2 ] [ 3 ] (B) The Attempt at a Solution [/B] Because the matrix A has the same number of columns as matrix B has rows, and because matrix A is an identity matrix...
  29. T

    Multiplication Table Question

    Why do many multiplication tables for grade school students go up to 12x12, when a table up to 9x9 is sufficient for any multiplication problem?
  30. pairofstrings

    How 'x' (multiplication) found its way into formula of area of rectangle?

    Hi, I know that area of rectangle is length x breadth. I tried to find proof of area of rectangle but I found that the proof was solved by taking formula of area of square into consideration. But what I don't understand is why area of rectangle should be length times breadth, or side times side...
  31. N

    Number of bacteria in a culture

    Homework Statement The number of bacteria in a culture is given by the formula n(t) = 700e0.65t, where t is measured in hours. What is the initial population n0 of the culture (at t = 0)? n0 = Approximately how many bacteria, N, will the culture contain after 5 hours? N = The Attempt at a...
  32. E

    MHB Show the Units of Zn with modular multiplication are a group

    I am trying to do an exercise where I am showing that the set of all elements of $\Bbb{Z}_n$ that are coprime with n form a group under modular addition. So far I have shown associativity, identity, and closure, but I'm having trouble showing the existence of an inverse. I know I can't use...
  33. M

    How well do you know the multiplication table?

    I'm now a 19 years old undergraduate physics student. I've a reasonable proficiency with calculus (well, no really...) but if you ask me 6*7 (unlike my mother and many other older people I know) I'll take awhile until I come up with an answer (I'll ask myself 6*5 and then add 12 to that result)...
  34. L

    Vector Multiplication in a Triangle on the Cartesian Plane

    Homework Statement For the vectors in a Triangle, with a = 16, b = 12, and c = 20 what are (a) the magnitude and (b) the direction of A x B (c) the magnitude and (d) the direction of A x C (e) the magnitude and (f) the direction B x C this is Vector Multiplication. Homework Equations...
  35. N

    Matrix multiplication, P1.1.1 Golub/Van Loan-Matrix Computations 3rd

    Hi, I am studying linear algebra from Golub G.H., Van Loan C.F.- Matrix Computations 3rd edition. This book is somewhat old now, but I find it rather comprehensive. I want to study all chapters and answer all problems appear at the end of each section. Here is the first problem from the first...
  36. Roodles01

    Vector Multiplication: Finding the Correct Solution

    Homework Statement Still having a little trouble so here's the problem. (ex + ez) x (3ey - 4ez) The Attempt at a Solution (ex * ez) + (ex * (-4ez)) + (ez * 3ey) + ( ez * (-4ez) now, these are all orthogonal to each other, so, for example, if I have ex * ey then I should end up...
  37. T

    Multiplication by different units

    Hi, What does N*m mean? What does N/m mean? What kWh mean? What kW/h mean? What does F=m*a mean? I read maybe all articles on web about concepts of multiplication,units,differences.But respondents only starts with some question(You know,what is dividing,but you do not know what...
  38. R

    Multiplication of conditional probability with several variables

    Dear All, I am a starter to machine learning and i am currently confused about the following problem: what is the result of P(X|Y)P(Y|Z)? In my book, it is written to be P(X|Z). But I don't think it is correct since P(X|Z)= P(X|Y,Z)P(Y|Z) But clearly P(X|Y)=/= P(X|Y,Z) Assuming...
  39. adjacent

    Java Javascript multiplication tables

    I am learning Javascript and have made a multiplication table generating program. But it's about 1000x slower than C#. Is there any problem with this code? I used the same code as C#, just the syntax is different. Here is the code: <html> <head lang="en"> <meta charset="UTF-8">...
  40. S

    Is Complex Multiplication Always Equal to Zero?

    Is this statement true? \bf{Re}\{z_1 \times z_2\} = 0 \,\, and \,\, z_2 \ne 0 \Rightarrow z_1 = 0 \,\,\, where \, z_1; z_2 \in \rm{C} Thanks.
  41. S

    Does multiplication by an invertible matrix preserve convexity?

    I am working with polytopes that are defined by half-planes in \Re^N. So they are defined by a number of inequalities (half plane representation), but can also be represented by the intersection points of these half planes (vertex representation). Computing the vertices is expensive, so I...
  42. M

    Array multiplication and array division

    Hi, in Matlab I encounter with two new operations for me which are array multiplication and array division. I want to learn that do they have physical applications in real world physics problems or are they be related with banking and accounting.
  43. adjacent

    C# [C#] Multiplication table program hanging

    This is my code: double of = 0; double from = 0; double to = 0; double ans = 0; private void button1_Click(object sender, EventArgs e) { Table.Items.Clear(); if (double.TryParse(Of.Text, out of) == true &&...
  44. N

    Understanding formulas involving divison and multiplication

    I've never quite understood is how formula can involve division and multiplication while dealing with abstract concepts. Such as, ohm's law V = I•R where V=voltage applied I=current and R=resistance. How does that work exactly? how can you multiply two abstract concepts together to understand...
  45. A

    Yaw,Pitch and Roll Multiplication

    If I have (α1,β1,γ1) and (α2,β2,γ2) as two set of rotation angles in radians.Where α is Yaw of α about z axis, β is pitch about y-axis and γ is roll about x axis. My question is when I multiply the two rotation sets what would be the result? Would it be simple addition of angles if I extract the...
  46. T

    Multiplication Table of C3V and P3 Symmetry Groups

    Can one set up a multiplication table for the symmetry group C3V of the equilateral triangle. Then show that it is identical to that of the permutation group P3. I need some clarification... What about a matrix representation (2x2) for these groups? → Here was thinking to use...
  47. C

    Matrix multiplication - is this plausible?

    say X = (AB) (B-1 C) B-1 = B inverse (B B-1 = B-1 B = I) then can i write X = AC? just having a brain fart moment. i would appreciate a speedy response, cheers.
  48. C

    MHB Matrix multiplication simplified to Vector multiplication

    Hello, I'm not sure where to put this. I have spent the last week (14+ hour days) editing some code I have for selecting representative spectra for a remote sensing masters thesis I'm working on. The program is very-very slow, and I've been trying to speed it up as much as possible by NOT...
  49. R

    A question about the cross product as related to matrix multiplication

    I understand that the cross product, in lay mans terms doesn't exist unless we're in 3 dimensions. When you multiply two matrices together I have been told you get something similar. I hear that this is because a matrix can be treated as a vector. So if we are talking about measurable...
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