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

Feb2313 09:24 AM
micromass

1 
36,237 
If A\in\mathbb{C}^{N\times N} is some complex matrix, is there anything we could say about the determinant of the...

Dec2212 08:15 AM
sfn17

2 
5,380 
I am reading the paper http://arxiv.org/abs/hepth/9701037.
In equation (2), the author write the determinat as...

Dec1812 04:26 AM
scottbekerham

1 
1,063 
hi
if F is inner automorphism , what does this mean ?
I think that if
F : G to G
then
we can write F(x) as ...

Dec1612 04:55 PM
Maths Lover

2 
829 
Suppose we have Asec(x) on the right hand side in a nonhomogenous ODE and in a Euler equation. How do we solve it? (...

Dec1512 07:51 PM
BackEMF

3 
943 
Im looking through old exams for a course in Cryptography and have beaten my head against the wall for a long time on...

Dec1512 02:55 PM
johnqwertyful

12 
2,303 
So Munkres, on page 424 of Topology (2nd edition) says that "...two free groups are isomorphic if and only if their...

Dec1512 10:53 PM
mathwonk

9 
1,227 
Hi, I was playing with Riemann zeta function on mathematica. I encountered with a quite interesting result. I iterated...

Dec2212 09:48 PM
Jeff Cook

10 
2,118 
If I have a point (x,y) and I rotate the axises by some amount. Why is x' = xcosθ+ysinθ and y'=xsinθ+ycosθ?

Dec1512 09:35 AM
Vargo

6 
900 
Suppose it is known that A is singular. Then the system Ax=0 has infinitely many solutions by the Invertible Matrix...

Dec1512 01:09 PM
Bipolarity

4 
1,280 
Let B={b1,b2} and C={c1,c2} be basis. Then the change of coordinate matrix P(C to B) involves the Ccoordinate vectors...

Dec1912 10:20 PM
bonfire09

2 
1,044 
Apart from simplifying matrix powers, why do we want to diagonalize a matrix? Do they have any appealing application...

Dec2212 06:03 PM
marxLynx

4 
1,295 
Suppose that \textbf{x} = A\textbf{x} + B\dot{\textbf{x}} where \textbf{x} is vector of economic output level, A is...

Dec1512 10:52 PM
mackenzies

0 
694 
Hi,
I have a quick question, when should one use RREF in finding eigvenvectors? I've read through some books and...

Dec1712 08:06 AM
HallsofIvy

2 
899 
Given a group G acting on a set X we get an equivalence relation R on X by xRy iff x is in the orbit of y.
My...

Dec1712 01:42 PM
Damidami

2 
803 
I know that we say two representations R and R' of a group G is equivalent if there exists a unitary matrix U such...

Dec2112 07:51 PM
micromass

2 
827 
Hey!
Is there an infinite ring with exactly two maximal ideals.
Thanks in advance
LiKeMath

Dec1912 11:29 AM
mathwonk

4 
1,260 
Eigen values of a complex symmetric matrix which is NOT a hermitian are not always real. I want to formulate...

Dec1912 12:00 PM
Robert1986

14 
2,209 
Hello everyone, first time poster, long time reader here!
I'm an exmath major and while I'm no longer pursuing a...

Dec2112 04:15 PM
johnqwertyful

5 
1,110 
Hello
Could anyone give an intuitive explanation of the determinant? I know mostly what the determinant means and I...

Dec1912 12:26 PM
mathwonk

4 
1,080 
Homomorphism is defined by ##f(x*y)=f(x)\cdot f(y)##. One interesting example of this is logarithm function...

Dec1912 06:36 AM
matematikuvol

4 
833 
Hey all, I have been playing around with a special type of matrix and am wondering if anyone knows of some literature...

Dec3012 11:21 PM
orthogonal

4 
1,500 
Hello,
If we have two vectors u,v then in an inner product space, they are said to be orthogonal if <u,v>=0.
...

Dec1912 11:11 AM
Erland

1 
974 
I am reading linear algebra by Georgi Shilov. It is my first encounter with linear algebra. After defining what a...

Dec2112 06:23 PM
Fredrik

5 
1,243 
Getting ready for linear algebra exam. One question that I got right but not exactly sure why is this:
...

Dec2112 03:38 PM
Frogeyedpeas

4 
1,114 
I have been trying to prove the following result:
If A is real symmetric matrix with an eigenvalue lambda of...

Dec2212 04:54 AM
matqkks

2 
1,066 
What is the best way of introducing singular value decomposition (SVD) on a linear algebra course? Why is it so...

Dec2212 03:19 PM
Stephen Tashi

2 
778 
Imagine we have two operators A and B on a complex hilbert space H such that:
\psi = (ABBA) \psi=c \psi \ \ \ \...

Dec2212 10:42 PM
micromass

6 
1,129 
Prof. Hugh Montgomery has been quoted as saying that it appeared that, if the Riemann hypothesis is true, the...

Dec2312 10:37 AM
nomadreid

0 
882 
Hello,
I was wondering, why is the vector projection useful in the way that it is presented? Why isnt just the...

Dec2712 03:30 AM
Stephen Tashi

12 
2,265 
Question is :
If m,k,n are natural numbers and n>1, prove that we cannot have m(m+1)=kn.
My attempt :
Using...

Dec2712 12:16 PM
mathwonk

16 
3,034 
I have an equation (constraint) which I wish to solve explicitly in terms of gd (or more precisely a scaling factor of...

Dec2512 02:42 AM
james1234

1 
871 
Video illustration
Hello,
Me and a friend, David Barrack, are nonmathematicians but we've been having fun...

Dec2512 11:34 AM
micromass

2 
2,073 
I was looking for a hint on a problem in my professor's notes (class is over and I was just auditing).
I want to...

Dec2812 06:42 AM
sammycaps

12 
1,322 
I've got a general question about Lie algebras, which is basically this:
Q: What is there to be said about the Lie...

Dec2712 01:10 AM
Couchyam

0 
774 
This may be a very silly question, but still apologies, I read in Sheldon Axler, that the inner product of two...

Dec2712 07:31 AM
vish_maths

3 
869 
The book I am going through says this :
The below proposition is false for real inner product spaces. As an...

Dec2812 06:46 PM
chiro

3 
1,012 
Is there any algorithm to form a magic square of any size with a desired magic sum ?
Also can we make a magic square...

Dec3012 08:09 AM
RamaWolf

6 
2,167 
Hi All,
I have a hard time answering the following. I need some help.
Let Z={a,b,c,d,e,f} and let X denote the...

Dec3012 01:31 PM
laptopmarch

1 
759 
Suppose that a = aBc where a and c are vectors and B is some matrix that changes as time "continuously" goes on ...

Dec3112 04:20 AM
dotiozeros

0 
813 
Hello everyone,
I found that you're actively discussing math problems here and thought to share my problem with...

Jan113 03:33 AM
phd_student

0 
1,038 