Multiplication Definition and 484 Threads

Perform the following operation in binary: 15X-7 The Attempt at a Solution I tried getting help on the engineering board, but nobody has helped yet, so I figured I would try over here... - I can't seem to figure this one out for some reason. My first attempt, I used...

15X-7 The Attempt at a Solution - I can't seem to figure this one out for some reason. My first attempt, I used 1111(15)X1001(2's complement of 7), but I can't get the right answer. I believe that the answer should come out to be the 2's complement of 105 since the actual answer is...

I have just watched a very interesting way of multiplying 2 numbers together, but i wonder if anyone could explain to me why it works. here is the link Calculating technique - 5min - Video cheers gabrown

1. I have a fairly straight forward problem (or basically, i need help to just get started on my problem), i have forgotten all my QM and am in a "bit" over my head here. Basically i am having problems remembering how one would go about treating operators that are inside exponentials. 2...

Homework Statement Does anyone know a generic way of showing that a field is closed under multiplication and addition? Please, thanks Homework Equations The Attempt at a Solution Just need to prove that a+b and ab are in the field that each element a and b are from. Any ideas??

Something that has bothered me in my linear algebra class was that I learned a lot of techniques but didn't learn why they worked, or what they were useful for. One of the things is this: why is matrix multiplication so useful in the way it's defined, and not in any other way? Of all the ways...

On a given day of a flu epidemic, a given percentage Y of the population is ill and (1-Y) is healthy. The probability of remaining healthy on the next day is a, and that of remaining sick is B. The question is, what percentage will be ill after a given number of days as a function of B,a and Y...

In engineering we're always taught block diagrams in communication systems, specifically multiplying two signals... How exactly do you multiply 2 separate signals electronically? What does the circuit diagram look like?

We all know BEDMAS from grade school: brackets, exponents, division, multiplication, addition, subtraction. My question is, why does multiplication precede addition, and likewise their inverse operations?

Matrix multiplication confuses me. How, for example, would I multiply these matrices: a b c d e f g h i x r s t u v w x y z ? Thanks!

Homework Statement Check to see if the (vector space) set of rational numbers is closed under addition and scalar multiplication Homework Equations The book says this holds for addition but fails for scalar multiplication. The Attempt at a Solution Im a little confused. You can...

Homework Statement Let B = 5.00m at 60 degrees. Let C have the same magnitude as A and a direction angle greater than that of A by 25.0 degrees. Let A*B = 30.0 m^2 and B*C = 35.0 m2. Find A. Homework Equations Pythagoras maybe. The Attempt at a Solution Well, if A*B is 30 m^2, and...

rather than use the standard definitons of addition and scalar multiplication in R^2, suppose these two operations are defined as follows. (x1,y1)+(x2,y2)=(x1,0) c(x,y)=(cx,y) what would the zero vector be? can it be (0,-y1)? why or why not? I think it should fail this axiom u+0=u.

What is \left(\begin{array}{ccc}1&1&2\\0&2&1\\1&0&3\end{array}\right)\left(\begin{array}{cc}1&1\\3&3\end{array}\right)? I'm so confuse because the first matrix is 3 columns matrix and the second matrix is 2 rows matrix. Thank you

Homework Statement Suppose one has n×n square matrices X, Y and Z such that XY = 1and Y Z = 1. Show that it follows that X = Z. The Attempt at a Solution Now I know if the equatoins had been XY and ZY I would do this: XY=ZY -> XY-ZY=0 -> Y(X-Z)=0 -> X-Z=0 -> X=Z I was wondering if...

As reported in Slashdot, http://it.slashdot.org/it/07/09/24/2339203.shtml "Excel 2007 Multiplication Bug"

Ok, this isn't a homework question -- more out of curiosity. But it seems so trivial that I hate to post it under "General Physics" We all know the standard formula for error propagation: \sigma_f = \sqrt{\dfrac{\partial f}{\partial x}^2 \sigma_x^2 + \dfrac{\partial f}{\partial y}^2 \sigma_y^2...

I wondered why it is that when you multiply a negative with a negative, you get a positive? in example; why is it that -3 x -3 = 9? when you do -3 x 3, the answer is intuitively -9, because you just go three times as negative. But when I multiply two minus signs, I don't have this...

Homework Statement Show by matrix multiplication, \delta_{ij}v_j = v_i The Attempt at a Solution I'm having trouble understanding how to do this, because I'm under the impression that v_j is a row vector, which can't be multiplied by a 3x3 matrix which \delta_{ij} is; or am I horribly...

Homework Statement Proved that the set of all rational numbers of the form 3^m *6^n are integers , is a group under multiplicationHomework Equations No equations for this particular proof The Attempt at a Solution Assume that all rational numbers are in the form 3^m *6^n . Therefor 3^m*6^n =...

Let A and B be real invertible n x n matrices so that B = (AT)-1. Show that Bm = (I - B1A1T)(AmT)+, where B1 = [b1, ..., bm], Bm = [bm+1, ..., bn], A1 = [a1, ..., am], Am = [am+1, ..., an]. Any pointers on how one would go about proving the above? I'm fresh out of ideas. I'm not...

Homework Statement A function f:R-->R^x is a homomorphism iff f(x+y) = f(x) + f(y) for all x,y in R Homework Equations I don't know what group R^x is. I can only assume it means Reals under multiplication . Would that mean that f(x+y) = f(x)f(y)? How does the function work? Since 5...

I was wondering, if you have the function: f(x)=A/B and the value returned is a non-integer, what form would the function g(x) have if it were to return the decimal part of the value returned multiplied by B? For example: A/B=3.245862 What function would return B*0.245862?(This is...

I would much appreciate if someone could direct me to a webpage that has examples of this. My book, Thomas Calculus, only has one example (elementary) and this is for self study so I don't have lecture notes to go with it. All the questions in it are on trig integrals if that's any help.

We know that infinite-dimensional matrix multiplication in general isn't asociative. But, is there any criteria when asociativity is valid? thanks in advance.

How come on step 3 it says to carry a 2nd 4? and What does it mean when it says that 40 is greater than 9? Where did the number 9 come from? What is it referring to? http://www.webmath.com/cgi-bin/k8ipcalc.cgi?op=mult&n1=808&n2=745&back=k8ipmult.html Thank you.

Hello! I am just invastigating the cubic function and proving my conclusion formally. I am finding the formula for the tangent to the function at the point equal to the average of two different roots. The function is: P(x) = q(x-a)(x-b)(x-c); after multiplication: P(x) = q (x^3 + (-a-b-c)x^2...

What simple operations, if any, precede or succeed the series ". . . exponentiation, multiplication, addition. . ."?

Hi I noticed that multiplication of all primitive roots modulo p ,p>3, congruent to 1 modulo p... I have tried some examples (13,17,19...) but i couldn't prove the general case (let g1...gk be primitive roots modulo p,p>3 ==> g1*g2*...*gk=1(p)) I need help to prove or disprove...

Homework Statement So I have to prove that addition and multiplication in Zn are well defined. Homework Equations The Attempt at a Solution I have no idea where to start.

Homework Statement Expand and simplify the product of two quaternions: (3 + 2i + 3j + 4k)(3 + 3i + 2j + 5k) Justify your response. The Attempt at a Solution I have done this by expanding brackets normally, keeping the ijk's in the same order because the multiplication is not...

please i need your help, this question is from my midterm exam ineed solution very quick, it is due next week! "your finger can provide an (n-1) multiplication table in base n, 2<=n<=10 as follow: hold n fingers in front of you. to multiply (n-1) by k in base n, lower the kth finger from the...

I found http://www.metacafe.com/watch/315070/cool_math_trick_really_fast_multiplication/" video tutorial about a week ago and got hooked on the method. It's really simple once you get into it and works wonders. It can be easily extended to bigger numbers as well. I can't understand why they...

Can someone explain "block multiplication" to me? It's not in the book, except in the context of a question as follows: So the rule is that Matrix [A B] * colum matrix [C D] = [AC+BD] And I am supposed to verify it. but can I just ask how I would go about doing that since I really don't...

Homework Statement "PRQSTU is a regular hexagon of side 2 units. PQ,QR and RS represent vectors a, b andc respectively. Find the value of a.(b + c) The hexagon is a regular hexagon starting at the far left (ie pointing left) with P then anti clockwise through U at the top left...

I want to write a C/C++ program and encounter a problem.If I have three 64 bit numbers and need to manipulate "a * b mod c" Is there any well-known, efficient and simple algorithm to implement it? I only know it can be calculated sth. like this.. __int64 a, b, c a = x1 * 2^32 + x0 b =...

I want to write a C/C++ program and encounter a problem.If I have three 64 bit numbers and need to manipulate "a * b mod c" Is there any well-known, efficient and simple algorithm to implement it? I only know it can be calculated sth. like this.. __int64 a, b, c a = x1 * 2^32 + x0 b =...

Homework Statement I know with hydraulic multiplication a small piston can create an increased force upward on a large piston. But if you take the small piston and pull upward on it creating a vacuum. Would the large piston have a multiplied vacuum force pulling it downward. Homework...

Amazing, does anyone know the algorithm behind this? http://www.metacafe.com/watch/296904/easy_mental_multiplication_trick/"

At a particular instant the location of an object relative to location A is given by the vector A = < 7, 6, 0 > m. At this instant the momentum of the object is p = < 20, 8, 0 > kg · m/s. What is the angular momentum of the object about location A? According to my book, angular momentum is...

Hello everyone, I'm new to this forum, and I've registered to seek advice on this topic. What I'm attempting to do is multiply two very large numbers together, represented as polynomials, by the use of the number theory transform (ntt). I've done much research on this topic and I've had some...

I know the set of positives rationals form a group under multiplication and that the negative irrationals do not form a group under multiplication because there is no identity or inverse. My question is does the set of all rational numbers under multiplication form a group.

Hello everyone! I'm having troubles with the "multiplication rule" which states: If an operation consist of k steps and the first step can be performed in n_1 ways, the second step can be performed in n_2 ways [regardless of how the first step was peformed], . . . the kth step can be...

Let G be a group and H a subgroup of G. The book claims HH=H because H is a subgroup. Group multiplication is defined as AB={(a,b): a in A, b in B} So HH should be ordered pairs with each pair containing two identical elements in H. But why is the answer H, which is not an ordered pair? I...

Are there 3 different multiplication tables for groups with 4 elements? The reason is that an element 'a' could have 3 different inverses, a,b,c. Each potential inverse will make a different table. Hence 3 different tables.

Multiplication table help please! Algebra ... Hi, I've come across this question in my algebra txtbook and the exercise asks to construct a multiplication table, verifying that the Quaternion Group forms a group under matrix multiplication. http://i12.tinypic.com/2i20wus.jpg I'm confused...

Why is it that when you do A * b/c the answer is one (b/c)th of A? What is the operation of multiplication doing to the two numbers so that this happens? Also how does this logic work when A is also a fraction?

Matrix multiplication is clearly defined but is there a tangible or physical interpretation for it? Or is it just abstract formalism? I am thinking about each column of the matrix as vectors so matrix multiplication with two 2by2 matrices is about multiplying 4 vectors in a certain way. The...

OK, so I'm writing a program and I want to calculate modular exponents. The only hard part is the multiplications. It would be best if I could work with numbers where, at all intermediate stages, each number is less than 2^64. If I must create a bit array I suppose I'll do that, but this would...

have a question about finding the multiplication table of say Z2[X]/(x^3+x^2+x+1). What are the steps in solving problems like this? Because I keep doing different problems and I end up making a mistake. All I need is an example or an explanantion. Any help is greatly appreciated