Math Forum / Mathematics / General Topics / May 2007

I have a gride of NxM nodes that works as follows. Each iteration,
each node multiplies the four connecting nodes (left,right,up,down) to
determine its next value. Node values are +/-1 so the grid doesn't
overflow with large numbers. I add a 1-node buffer around the grid of

Given three positive real numbers which obey the triangle inequality, then
we may construct a triangle in the euclidean plane (unique up to congruence)
which has those values for side-lengths.
What are the restrictions on six lengths such that they may comprise the

if f(-x) = x^2 - 2x, evaluate f(x+h)
I am not sure if my thinking is correct, could someone correct me
please?
the independent variable is minus x, the value of it is -(x+h), so I

What is known about estimate of iterates?
Some trinoms such as T(x) = x^2+4x+2
or (x+2)^2-2 are easily iterated
T^[n](x) = (x +2)^(2^n) - 2  , n positive integer.

what is a wave ?
i mean a wave in physics.
not just a waterwave or sound.
but electromagnetical waves , light etc.

I am a computer scientist and am studying the effects of force
feedback on mouse movements.  So I have cursor traces of the movements
and some of them seem to have somewhat regular curves in them, I was
wondering how to mathematically describe the curve in a line.  The

After having had a lot of fun going through Chapter 10 of Rudin's
'Principles of Mathematical Analysis' (the chapter on differential
forms and integration), I am hungry for more of this stuff.
Can anyone recommend a good differential geometry textbook (preferably

حصريا صور مثيرة جدا جدا لهيفاء وهبي سارع التحميل - في الكبارية
حصريا فضيحة اية الشميري بالصور
www.3tr.net/vb/register.php
اول فتاة خليجية (اماراتيه)???

Let A be a matrix of the following form
 +  +  +  +  +
 +  +  +  +  0
 +  0   +  +  0

Williams (Prob. and Martingales) quickly mentions that every open subset
of the reals (standard topology) is just a *countable* union of open
intervals. This is not at all clear to me? Could someone please explain
or prove this?

Hello sir~
A, B are positive definite symmetric n x n square matrix.
Show that
{det(A+B)}^(1/n) >= (det A)^(1/n) + (det B)^(1/n).

Puzzle:  to what two-word string can " Simons" be appended to produce
the diametrical opposite?

Can some one help me with this puzzle:
A sequence of numbers
Solve for D - and describe the significance
37, 63, 24, 28, 48, 40, D

Can anyone recommend some references in terms of the stated skill
level in the title of this post? (partial derivatives, vector calculus
etc)
thanks

Hi I am Maha from pakistan. I am a student of M.Sc. in math Plz tell
me wat is the basic concept of  vector space in linear algebra