Math

Minus operator and no subtraction below zero
You cannot take away from a quantity more than its absolute value. You canot subtract from zero. The minus sign for a negative number is only real as a subtraction operator. Mitch Raemsch ... 11 Jun 2010 15:55

About Linear Independence of Exponential Functions defining an alternating serie
Hello to all, My question is: let the alternating serie ∑ (-1) **n-1*an*exp(i*β*ln(n))=0, where (an) is real and i is the complex number, ln(n) is the logaritm of n. The sum is taken over all natural numbers n>=1. I wonder if the above equation (the serie=0) implies that all the coefficents an=0 for all n. I a... 10 Jun 2010 02:23

Cosmic Blackbody Microwave Background Radiation proves Atom Totality and dismisses Big Bang Chapt 3 #149; ATOM TOTALITY
II. Cosmic characteristics and features; support Chapter (3) uniform blackbody 2.71 K cosmic microwave background radiation and Dark Night sky: Olber's Paradox fully answered Most scientists when they talk about the Cosmic Blackbody Microwave Radiation are deceiving because they neglect the word "blackbody". ... 8 Jun 2010 16:03

Gauss curvature of surface represented by real part of an analytic function-
gudi wrote: If u(x,y) ,v(x,y) are real/imaginary parts of an analytical function f( x + i y), under what conditions does surface Z = u(x,y) ( in Monge form ) have a positive Gauss curvature K? For most of the functions I find K is negative. Is it always so? Please give examples when K >0. TIA, ... 11 Jun 2010 08:08

Gauss curvature of surface represented by real part of an analytical function
If u(x,y) ,v(x,y) are real/imaginary parts of an analytical function f( x + i y), under what conditions does surface Z = u(x,y) ( in Monge form ) have a positive Gauss curvature K? For most of the functions I find K is negative. Is it always so? Please give examples when K >0. TIA, Narasimham ... 8 Jun 2010 13:44

An inequality
Let e(x)=x^x. Show e(a+b)^2 e(b+c)^2 <= e(a) e(b)^2 e(c) e(a+2b+c) for all a,b,c >= 0, with equality iff b^2 = a c. This arose in something I'm working on -- that it's true follows trivially from what I was doing. However, it doesn't seem obvious when stated in isolation. ... 11 Jun 2010 10:20

Online Interactive Statistics Courses for July and August
Interact with our experts. Participate from office or home at your leisure. Ask questions, discuss difficulties, and make comments 24/7 via the on-line discussion board. For more information, see http://statcourse.com. Analyzing Large Numbers of Variables—Microarrays, EEG's, MRI's. This 4-week course will show y... 8 Jun 2010 12:35

Integrals and Polynomials
Hello, let R be the field of real numbers and f:[0,1]->R a continuous function such that, for every positive integer n, we have int_{0 to 1} f(x)*(x^n) dx = 0. Is f(x)=0 for every x in [0,1]? Thank you very much for your attention. My Best Regards, Maury Barbato PS If we assume also that int_{0 to 1... 15 Jun 2010 04:21

Interpretation of solutions to problem involvingdifferentiation
> A reservoir is being emptied, and the quantity of water, V m ^ 3 , remaining in the reservoir t days after it starts to empty is given by V (t) = 10 ^ 3 * (90 − t) ^ 3. After what time is the reservoir being emptied at 3 * 10 ^ 5 m ^ 3 / day? -3 * 10 ^ 5 = -3 000 * (90 - t) ^ 2 ... 8 Jun 2010 08:03

Elementary Mathematics From An Advanced Standpoint
Does anyone have any information regarding the third volume of Felix Klein's "Elementary Mathematics From An Advanced Standpoint"? It seems it was never published but I thought I'd ask all the same.I've just finished reading the first two volumes are they are still fantastic 100 years on. ... 9 Jun 2010 01:00