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

Feb2313 09:24 AM
micromass

1 
35,756 
X^3+PX+Q=0
X_0 = A + B
(A+B)^3 + P(A+B) + Q = 0
A^3 + B^3 + (3AB+P)(A+B) + Q = 0
The next step is 3AB+P=0

Oct1710 12:39 AM
kennysmith39

3 
3,023 
I just started reading the first chapter of Georgi Shilov's "Linear Algebra" and I have a question about his notation...

Nov2810 04:57 PM
RBNYC2

3 
2,842 
I am looking for a rather simple proof that if the matrix A has eigenvalues>0, then (x^t)Ax>0 for any vector x not 0....

Aug2310 08:00 AM
HallsofIvy

3 
1,367 
Thank you for reading.
If I have an object (is it correct to call it a tensor?) whose components are defined by:
...

Aug2610 12:55 AM
Fernsanz

3 
1,295 
There is a problem in a book I'm not quite understanding.
Let M be an Rmodule and let I=Ann(M). Show that M can be...

Aug2610 03:58 AM
Hurkyl

3 
776 
normal extension  an algebraic field extension L/K is said to be normal if L is the splitting field of a family of...

Aug3010 05:57 AM
rasmhop

3 
2,020 
Help for prove this please
Let T\in{L(V,W)}
The equation Tx=y have one solution iff y\in{R(T)}

Aug2810 12:41 PM
arkajad

3 
925 
Yet another silly question from me :/. From an instructor's notes: "Let V = R^n be the vector space of column ntuples...

Sep110 02:39 PM
vanckzhu

3 
1,901 
Definition: A semigroup is a pair (R,op) where R is a set an op is a binary operation that is closed and associative. ...

Sep810 06:27 AM
Eynstone

3 
1,274 
Consider a binary operation on a set G. A an element e of G is said to be a left identity if ex=x for all x. If x is...

Sep410 08:53 PM
Fredrik

3 
5,744 
0, 1, 1, 1, 2, 2, 4, 8, 12, 96...
What number follows?

Sep510 03:11 AM
adriank

3 
1,036 
Are there cases where there's more than one binary operation to choose from by which to define a Lie algebra for a...

Sep1010 10:47 PM
Rasalhague

3 
984 
what will be the sum of this series?
\Sigma nCr . 2r
where r = 0 to n

Sep1510 02:22 AM
Sherard

3 
1,169 
Appoint all the pairs (k, l) (both k and l in R^+) such that:
\sqrt{k}+\sqrt{l}=\sqrt{4+\sqrt{7}}
I'm really stuck...

Sep1210 09:44 PM
adriank

3 
1,058 
I was wondering what would be the largest possible value for a determinant, for a 3 by 3 matrix whose entries can only...

Oct1110 06:42 PM
Simon_Tyler

3 
4,262 
I'm reading the first chapters of "A Guide to Distribution Theory and Fourier Transforms".
On page 10, Exercises...

Sep1910 01:21 PM
Goldbeetle

3 
974 
what is another way to form (a+b)^c to another simple expression?
like for example a^c+b^c doesnt work because its...

Sep2010 10:12 PM
GlobalDuty

3 
1,162 
When I realize that I am going to have a singular matrix (after exhausting row swap options and maybe even some...

Sep2210 09:50 PM
MurdocJensen

3 
12,315 
Here is my problem. Any ideas are appreciated.
Let P be a projection matrix (symmetric, idempotent, positive...

Sep3010 06:28 AM
trambolin

3 
6,888 
not hw question and i say yes.

Oct2810 03:52 PM
Outlined

3 
864 
I read the following on the wikipedia page about simple rings (http://en.wikipedia.org/wiki/Simple_ring):
I do...

Oct310 10:32 PM
gerben

3 
1,126 
Sounds great thank you

Oct310 04:28 PM
Simon_Tyler

3 
1,150 
Hello everyone. I was going through my Linear Algebra Done Right textbook that threw me off. I hope this forum is...

Oct410 11:17 PM
adriank

3 
5,095 
Is it true that if a finite group G contains a subgroup of index 2, then there is an element of G with order 2?

Oct810 10:08 AM
ForMyThunder

3 
823 
I saw the following problem on my abstract algebra book (dummit && foote) , I tried to solve it but I couldn't :
Let...

Oct1110 04:03 AM
hermanni

3 
1,742 
Let V be a finitedimensional vector space over the field F and let T be a linear operator on V. Let c be a scalar and...

Oct1210 12:49 PM
arkajad

3 
1,570 
Do all linearly dependent sets have elements that are linear combinations of each other? Or does this apply only to...

Oct1210 10:21 AM
ichigo444

3 
1,064 
Can i use the invertability of a matrix as an alternative way of determining the linear independence of a set? Thank...

Oct1210 10:54 AM
Wizlem

3 
938 
I expanded (x+y),(x+y) and got x^2+y^2 > 2xy then replaced 2xy with 2x,y but now I'm stuck.
I need to get it to...

Oct1510 10:14 AM
Rederick

3 
4,806 
I think I understand most of this Wikipedia page on the interior product ("not to be confused with inner product"):
...

Oct1710 02:01 PM
Rasalhague

3 
1,992 
Since my late interests have been related to networks, I've started a pet project focusing on natural numbers network....

Oct2110 03:27 AM
networks

3 
1,605 
Hey there, physics forums!
A question occurred to me the other day: Is it true that if f \in \mathbb{Z} is monic...

Oct2110 05:26 PM
CRGreathouse

3 
1,450 
We have vectors x,y of size n and a matrix A of size nxn.
Is it true that the matrix xyTA has at most one non zero...

Nov410 09:27 AM
Outlined

3 
1,509 
Prove that the collection F(N) of all finite subsets of N (natural numbers) is countable.

Oct2810 05:05 PM
willem2

3 
2,147 
Hi,
I ran into conflicting definitions of integral domain. Herstein defines a ring where existence of unity for...

Nov710 04:10 PM
mathwonk

3 
1,420 
I was wondering, if we want to define a morphism from
\mathbb{Z}2006 to, lets say \mathbb{Z}3008.
Obviously, all...

Nov710 04:48 PM
Outlined

3 
1,189 
Im struggling to find proof for this suspicion I have;
Given is a function f(t) and a normalised function h(t), and...

Nov2410 10:22 AM
gerben

3 
1,738 
Question: Show that if R is an integral domain then R^x=R^x(or that the units in R are precisely the units in R, but...

Nov1910 08:49 AM
mathwonk

3 
2,211 
Some one please help me how to prove the following:
\dot{A}:B + A:\dot{B}=A^{\nabla J}:B+A:B^{\nabla J}
A and B...

Nov2110 03:55 PM
josh_machine

3 
3,549 
Hi, I read that the general form of an inner product on \mathbf{C}^n is:
\langle \vec{x} , \vec{y} \rangle =...

Nov2210 08:38 AM
andresordonez

3 
2,196 