
Please post any and all homework or other textbookstyle problems in one of the Homework & Coursework Questions...

Feb2313 09:24 AM
micromass

1 
45,414 
If f : Rn > R is Lebesgue measurable on Rn, prove that the function F : Rn * Rn > R defined by F(x, y) = f(x  y)...

May2011 09:48 AM
Eynstone

3 
1,285 
In a book I'm reading, it says:
If beta is orthogonal to the set A, then beta is orthogonal to the closure of the...

May2011 08:26 AM
micromass

4 
1,008 
Most of the time I can visualise whether some solids of revolution are annulous or not but sometimes I just don't see...

May2011 07:04 AM
kr73114

4 
1,172 
How do I find the Laurent expansion of a function containing the principal branch cut of the nth root?
Example:...

May2011 06:59 AM
HallsofIvy

4 
2,054 
I understand that the limit of the sum of two sequences equals the sum of the sequences' limis: \displaysyle...

May2011 01:32 AM
dimitri151

6 
5,843 
Hi there,
I'm really ashamed of doing this stupid question but I really need help with this thing. And, even if it's...

May1911 09:35 AM
matteo86bo

2 
897 
let be the Fourier transform
G(s) = \int_{\infty}^{\infty}dxf(x)exp(isx)
with the properties
f(x) and ...

May1911 05:46 AM
henry_m

1 
785 
I came across in a journal that for a \nabla\times A=0 where A is vector, if ycomponent of that A is uniform then...

May1911 05:13 AM
henry_m

6 
1,750 
I have been deriving a formula from physics. Anyway, I came across a equation that goes by the form y = exp(1/(xy))...

May1811 08:58 PM
dm164

2 
1,026 
So, in integrals that lead to inverse hyperbolics and can be solved with trigonometric substitution i just get lost. I...

May1811 04:37 PM
coelho

2 
987 
let f: X\rightarrow be a positive, measurable function on a sigmafinite measure space (X,A,u). If p>0, show that
...

May1811 04:31 PM
justin_huang

0 
671 
can a function in ONE dimension have NO inverse ?? i mean
if given the inverse function f^{1} (x) = g(x) +...

May1811 12:48 PM
lavinia

4 
1,041 
A book I'm reading now says the graph of f(x)=1/x is a closed set, how come??
Its range is . A set is closed iff...

May1811 12:29 PM
spamiam

4 
2,024 
I'm trying to take the derivative of a min function.
I have some function that depends on the variable x and a...

May1811 07:26 AM
chanttd

3 
6,486 
1. a sequence in R having no convergence subsequence
2. nonconvergent sequence in R such that the set of limit...

May1811 01:10 AM
JG89

3 
799 
Hi, I'm trying to find the book Differential and Integral Calculus by Gregor M. Fikhtenholz, however I've only found...

May1711 08:43 PM
fgyamauti

0 
653 
Can someone help me prove the identity
\ u \times (\nabla \times u) = \nabla(u^2 /2)  (u.\nabla)u
without...

May1711 07:05 PM
henry_m

7 
2,293 
I'm currently reviewing calculus that I learned 10 years ago, because I will be resuming an electrical engineering...

May1711 05:13 PM
Nebuchadnezza

4 
971 
I came across this problem + solution:
http://imageshack.us/m/715/2962/inteyk.png
but I don't understand the...

May1711 03:33 PM
HallsofIvy

12 
1,683 
Hi, I am working on a project for my research and am need of some advice.
My background is in computer engineering /...

May1611 11:01 PM
Stephen Tashi

1 
2,327 
Recently I have been self teaching myself complex analysis.
I am interested in the conformal mapping property of...

May1611 05:08 PM
henry_m

3 
1,234 
Lee 2003: Introduction to Smooth Manifolds (...

May1611 01:48 PM
Rasalhague

2 
1,127 
Show that the subsets of the plane are open:
1.) A= {(x,y)1<x<1,1<y<1}
2.) C= {(x,y)2<x2 + y 2<4}
I have no...

May1611 12:01 PM
dimitri151

7 
4,515 
If I'm lucky enough to pass Precalculus this semester, I'll be taking Calculus 1 next semester. Just out of curiosity,...

May1511 12:32 AM
Bogrune

17 
7,707 
for example int. (1+x^2)^0.5 dx
why do you use x= tan u
i mean obviously because it works, but if you didn't know...

May1411 03:35 PM
paulfr

7 
2,338 
Hello every one, now I'm dealing with a series
a(k) = k^(s)e^(tk), s,t > 0
I want to find a continuous function to...

May1411 04:35 AM
Char. Limit

8 
1,975 
Hi.
I've been studying for a test and have been scouring my text for methods of proving points in 3dimensional space...

May1411 02:26 AM
paulfr

10 
15,163 
Hello
The problem is
find the value of \lambda for \lim_{n \to \infty} \frac{a_{n+1}}{a_n} \nonumber\ < 1, where
...

May1311 10:26 PM
alejandrito29

2 
655 
Have I got the following definitions right. That's to say, do they express the idea behind "big oh" and "little oh"...

May1311 11:23 AM
Rasalhague

2 
1,156 
So I'd like to start out by asking why the interchanging of limits is phrased in terms of the property of uniform...

May1311 11:10 AM
micromass

1 
1,035 
I have difficulty in understanding why the differential d\varphi of a function \varphi: \eta \rightarrow F(\cdot,...

May1311 10:42 AM
yifli

0 
557 
Hello!
I am trying to transform a circle into a "quarter moon shape". This is that every point in the circle is...

May1311 09:37 AM
Carol_m

5 
1,079 
\documentclass{article}
\usepackage{amssymb,amsmath,amsbsy,amscd,fancyhdr}
\usepackage{eucal}
\usepackage{tikz}...

May1211 11:06 PM
rbwang1225

8 
1,265 
I feel like I have gone pretty far in math now, but I keep finding myself asking the same question.
Say I had a...

May1211 02:22 PM
HallsofIvy

6 
1,862 
I am assuming that the solution was arrived at through integration by parts, however I am not able to completely work...

May1211 08:36 AM
DiffusConfuse

4 
1,047 
Lee: Introduction to Smooth Manifolds, definition A.18:
He then shows, by the chain rule, that
D_vf(a_0)=...

May1211 07:15 AM
Rasalhague

3 
1,597 
I have a question about the (ε, δ)definition of limit
lim x>a x^5=a^5
I know that x^5a^5<ε
and xa<δ
I...

May1211 07:10 AM
HallsofIvy

4 
2,155 
Let's say I have a function that preservers ordering i.e if x<y then f(x)<f(y) for all x. Obviously it must follow...

May1211 12:44 AM
Mark44

2 
1,013 
i want to compute the integral
\iint_{D} f(x,y)dxdy here f(x,y) is a Rational function and the integral is...

May1111 05:18 PM
henry_m

4 
963 
Let \vec w(t) \;,\; \vec v (t) be 3 space vectors that is a function of time t. I want to verify that:
\frac...

May1111 03:15 PM
yungman

4 
874 