Domain Definition and 743 Threads

Domain Functions: f(x) = 4sq.root(1-x2), the 4 is on the outside f(s) = sq.root(s -1)/s-4 f(x) = x-4/sq.root x I have absolutely no clue how to go about doing any of these, I take notes but I cannot piece it together; I have never felt so helpless at anything. This isn't homework I...

Hi, I've been trying to understand more on frequency plots of images. 1. Assuming a 1d example of just a strip of an image; in the frequency map there are 'same' no. of frequencies as there are pixels. What is the reason for this? Does this have something to do with the Nyquist theorom...

Hi everybody, I have question: Why can you do Convolution filter in the frequency Domain ? I mean, when you apply a filter to an image in the spatial domain, it 's easy. You've got for example your sobel 3x3 kernel that you apply on every pixel of your image. Easy. But when you convert...

http://www.starstreamresearch.com/vacuum_reaction.htm" I know this sounds like a lot of crackpottery, especially near the end of the article, but is there any scientific evidence in support of something like this happening?

Whatever is a schlicht domain (complex analysis)? Laura

I've just discovered why my emails are bouncing back from particular friends. Those friends have AIM accounts (or similar), and it seems AOL (or other) has blacklisted my domain. A few months back my site was hacked and someone was using it for phishing. With the help of my ISP I've deleted...

This is more of a math question but i feel like i will get more help among Electrical Engineers. I successfully found the step response of an RC circuit in the time domain using Laplace Transforms. But i can't seem to figure out how to do it with an RLC transfer function. I have the following...

Does anyone have a textbook on multivariable complex analysis, and do they define a holomorphically convex domain in terms of the union of an ascending series of compact subsets? If so, how exactly does the definition go? Was it D=\bigcup K_n where K_n is holomorphically convex and compact...

Homework Statement Given a,b,c in D, with a not 0, we have ab=ac implies b=c. Show that the commutative ring D is an integral domain. The Attempt at a Solution I don't know where to begin with this.

Consider a simple alternating current generator such as Hippolyte Pixii's dynamo. The current generated by such dynamo can be described as simple oscillating cosine signal. Assuming for simplicity that the max current generated each time a pole of Pixii's magnet passed the coil is (2/pi)0.5...

How do you convert functions from the time domain, to the frequency domain For example: cos(250t + 30degrees) is what in the frequency domain? Are there some general steps I can follow to do this?

What is an empty relation? Can an empty relation be a function? Is an empty relation one with the empty set as its domain or as its range or both? THanks

I'm doing some exam revision and there's a few questions on finding the domain and range of functions of 2 variables. With a function of 1 variable I know that the domain and range is just finding the max and min x value, and the max and min y value. With a function of 2 variables I am...

Homework Statement Prove that the nonempty fibers of a map form a partition of the domain. The Attempt at a Solution Ok so we have some map phi: S -->T And we want to show that its pre-image phi-1(t) = {s in S | phi(s)=t} forms a partition of the domain. Im really confused here. I assume...

Homework Statement Show that R = {0.5(a+b(root2)) : a,b are integers} is not a domain [b]2. Homework Equations A commutative ring (non trivial) is a domain iff (ab=0 => a=0 or b=0) The Attempt at a Solution I've try to construct a counterexample where x, y in R and xy=0 but x,y=/=0...

Domain and range in ovals--what's this called? I was helping my friend with his math homework. He's in an intermediate algebra and is working on domains and ranges of functions. He came to me for help with this method of describing domains and ranges of functions using two ovals--one listing...

I just have a question which I'm confused about, this is the same right? Domain is (-∞,0) U (0,+∞) and Domain D: {XER, x ≠ 0} and this is the same right? Domain is (-∞,0) U (5,+∞) and Domain D: {XER, x ≠ 0, x≠ 5} Attempt : I know that U is used to...

Homework Statement Find a. (f+g)(x) b. (f-g)(x) c. (fg)(x) d. (f/g)(x) f(x)=2x-5 & g(x)=4 Homework Equations (f+g)(x)=2x-1 (f-g)(x)=2x-9 (fg)(x)=8x-20 (f/g)(x)=2x-5/4 The Attempt at a Solution When I've completed all the other equations, I'm stuck on domain. I'm thinking that its all...

hi this is my first time here. i have just been admitted to the university of the gambia last month. i have a problem with this question. please i need help find the domain f is such that x maps to 1 all over the squareroot of x2-10x+12.

We recall that Z is the set of all integers. For each i, j in Z, let f(i,j) be the larger of the two integers i and j. Do these remarks define a function? If so, what are the domain and the image? I'm not sure how to do this. I believe that the remarks do define the function. But I don't know...

Can you find an example of a simple domain not being skew field?

Why is the domain of arctan power series |x|<=1? i understand why a power series has the domain |x|<1, but why is the power series of arctan |x|<=1? thanks! also, why are domains of the taylor expansions of coshx and sinhx: for all x?

Write down the domain and range of the function g(x) = 1 / ((9 - x)2) Please enter your answer as a list [in brackets], using inequalities e.g. a domain (for x) of (-¥, 2) and a range (for g(x)) of (2, 5] may be entered as: [x < 2, 2 < g(x) and g(x) <= 5] I don't get it??

Homework Statement y= \frac{x + \frac{1}{x}+1}{x+\frac{1}{x}+2} That is equal to y = \frac{x^2+x+1}{(x+1)^2} Whenever I graph either one of those they are the same graph (as well they should be) and they have a value for x=0. But why should x = 0 be in the domain? And also if you go...

This is not for a specific problem, just in general: If we want to find the double integral of a function of two varaible, when we got other 1 varaible function to define the domain. What are the basics of drawing the domain in 2d (x, y only)?

Identify the domain and range for the function f= {(x,y) \in \mathbb{R} x \mathbb{R}:y=\chi _{\mathbb{Z}}(x)} f={(x,y)\in \mathbb{R} x \mathbb{R}:y=\frac{e^x + e^{-x}}{2} How do I determine the correct results. I am not really understanding the terminology.

Homework Statement y = \frac{1}{(x-1)(x+2)} find out the domain and range ans: y<= -4/9 or y>0 x~E~R~-\{-2,1\} The Attempt at a Solution I know the solution and I used this methoD: y(x^2 + x -2) =1 (where y\neq0 ) when x is real, the discriminant y^2...

Find the derivative. State the domain of the function and the domain of its derivative. f(x) = x + √x f(x) = (3 + x) / 1-3x Find F'(a) f(x) = (x^2 + 1) / (x - 2) f(x) = √3x + 1

I'm trying to find the wiki page (if it exists) on the domain-straightening theorem and the range-straightening theorem but searches for those words produce no results. I've also seen those theorems by the name of "canonical forms for submersion and immersion" (in Gallot-Lafontaine-Hullin)...

Hi! I have to integrate on a triangular domain \int_T f(x,y,z)dxdydz so I use simplex coordinates, i.e. x=(1-\alpha-\beta)x_1+\alpha x_2+\beta x_3 y=(1-\alpha-\beta)y_1+\alpha y_2+\beta y_3 z=(1-\alpha-\beta)z_1+\alpha z_2+\beta z_3 where (x_i,y_i,z_i) are the vertices of...

x = 2cot t y = (sin t)^2 t is greater than 0 but less than or equal to pi/2 The cartesian can be found using trig identities to be: y = 8/ (4+ x^2) What would be the range of the cartesian equation? I think it would be x is greater than or equal to 0, since when t = pi/2, x =...

The function f is defined by f(x) = ln(4 - 2x), x<2, and x is a real number write down the domain of the inverse. I know that the domain of the inverse is the range of the function, but I am puzzled as to what that would be! Would it just be any real number? Thanks

If f:\mathbb{R}^3\to\mathbb{R} is a continuous function, x_0\in\mathbb{R}^3 a fixed point, r>0 a fixed radius, and n\in\mathbb{R}^3 a fixed vector satisfying |n|=1, then is the equation \int\limits_{B(x_0 + \alpha n, r)} d^3x\; f(x) \;=\; \int\limits_{B(x_0, r)} d^3x\; f(x) \;+\...

Hi All, I have some problem about my Fortran program. When I execute my program, it says Run-time error M6201-MATH -atan2 : Domain error I don’t know what to do. Please help me out from this error. Thanks Logi

So...a cosine wave when shown in the frequency domain is represented by a 1/2 magnitude vector at the positive frequency and a 1/2 magnitude vector at the negative frequency. I am surprised by this because I cannot understand why a vector of magnitude 1 at the positive frequency of the cosine...

How do you set up an integral integrating two functions within a domain?? Homework Statement I have to integrate (2 + x + y) within the domain that is the area between 0 and 1 and (x+y<=1) I know how to integrate well, I think it's a double integral but I'm not really sure what the range...

Homework Statement (1/(x+7))-5 find the domain and range. im having trouble graphing this one on my calculator, because when i zoom out the graph looks a lot different than when i zoom in. i think i have an answer though, so i need a quick check. domain: none (infinite) rangE: 0 to -10?

What's the difference between "Electron Domain Geometry" and "Molecular Shape"? Please help! Thanks

for g(x) = (x-2) / (x^2 -9) the domain of the function would be simply to have the denominator not equal to 0, which in this case would be x = 3. but.. the solution states that it is -3 and 3 cannot be used. this is confusing seeing that -3^2 -9 = -18 which is not 0. maybe it...

Homework Statement Approximate the solution of: \frac{\partial^{2}u }{{\partial r^{2} }} + \frac{1}{r}\frac{\partial u}{\partial r} + \frac{1}{r^{2}}\frac{\partial^{2}u}{\partial \theta^{2}} = 0, 1<r<3, 0<\theta<\pi, u(1,\theta) = 1-\cos(\theta),u(2,\theta)=u(r,0)=0 u(r,\pi)=4-2r...

What would the domain of y = sqrt(cosx) be in mathematical terms. I know that it is all the reals that lie in the first and fourth quadrant of the unit circle, but how would you express that in mathematical terms?

i have a question about laplace transforms. I had to find the maximum of a three exponential equation f(t). What I have done is took the first derivative of f(t) and equated it to zero. Now f'(t) is also a three exponential equation ( like f'(t)= e^at +e^bt +e^ct). So I have taken laplace...

Homework Statement i have a question about laplace transforms. I had to find the maximum of a three exponential equation f(t). What I have done is took the first derivative of f(t) and equated it to zero. Now f'(t) is also a three exponential equation ( like f'(t)= e^at +e^bt +e^ct). So I...

Homework Statement State if the following is a function. If yes, write domain and range. A. {(x,y): y=(x^1/2) ; x,y are real numbers and x>0} B. {(x,y): y^2=x ; x is real numbers and x>0} Homework Equations A relation is called function if each element of the domain...

Find the particular solution y=f(x) to dy/dx=(1+y)/x given that f(-1)=1 and state its domain. My answer was: 2|x|-1, x ∈ ℝ/{0} Apparently, the domain should be x<0 Solving the differential equation was not an issue at all, but I have no idea why the domain is restricted to x<0. I...

Homework Statement I don't really know how to ask this, so I'll get straight into an example. x:x\in(-\infty,\infty) but x\neq1 x:x\in(-\infty,1)\cup(1,\infty) what is the difference between these two intervals? Homework Equations The Attempt at a Solution

[SOLVED] Is 0 a prime? Am I missing something or is 0 a prime element in an integral domain? In the definition of prime element p of an integral domain, we only ask that the ideal generated by p, be prime. Well (0) is obviously prime because if ab=0 in an integral domain, then it is that...

If f(x,y) = e^{-x-2y} find P(X<Y) . So is this equaled to 1 - P(X>Y) = 1 - \int\limits_{0}^{\infty} \int\limits_{0}^{x} e^{-x-2y} \ dy \ dx = \frac{1}{3}?

Homework Statement I have to do a few graphs and some equations with certain domains but I've never seen the domain written in this way: Usually I see the domain written with something like 2<x<4. What exactly does the above mean?

Calculus Help, Please. (Domain, Range, Graphs) Homework Statement Determine its domain and range. f(x) = {2x+1, x<0 {2x+2, x => 0 f(x) = {x^2 + 2, x<=1 {2x^2 + 2, x >1 f(x) = { |x| + 1, x<1 { -x +1, x=>1 Homework Equations No equations...