Recent content by evad1089

Did you ever find out the answers yinx?

Ch 1.4 :D I figured the three masses had six because the object could move in three space (3) and could rotate in three space (3). 3+3=6 I figured the two masses had five because they could move in three space (3) and could rotate in three space (3) but rotation around the rod was not...

I am using it currently. I have no idea about the solutions though.

For anyone who stumbles across this in the future, my problem turned out to be two fold. First, floating point rounding errors in calculating the phase cause a lot of jumps of pi. Second, the FFT is in forward time, ie t>0. This is a phase shift. There are charts and such, depending on the...

I have tried MatLab, Maxima, and Mathematica. Currently I am using Octave (free MatLab style program). I also have been using fftshift. Here is what I mean with the phase. The below two picutures are of the phase of a Gaussian Beam. The first is the continuous transform and the second is the...

I have about 40 tabs open on this right now and something important is slipping my grasp. I know this has been covered a million and a half times, but for some reason I cannot seem to find a straight answer (or more probably realize and understand it when I see it). When I take the Continuous...

I bet you could also use the function: u''+a2u' = eibx and split the real and imaginary portions with Euler's formula. I find e easier to work with than sin and cos.

If you nice folks will tolerate a few more questions, I would be eternally grateful. I am still wrapping my head around the concept of phase; it seems a little more tricky that magnitude. Here is the magnitude of the fft of my function: http://blackbricksoftware.com/custom/imagem.png It is...

Thank you. I have a secondary question related the fft. Taking the fast Fourier transform of the top hat returns a set of complex valued data points. Obtaining the magnitude of these points is quite easy, but phase is eluding me. It should be something like '_-_-_', switching at the places the...

I have been playing with the FFT and graphs. The easiest example I could think of for a transform was the top hat function (ie 0,0,0,0,0...1,1,1...0,0,0,0,0). When I transform this from the time domain to the frequency domain, it returns a sinc function when I take the absolute value squared of...

Well, I got frustrated and decided that a qualitative answer about the properties of a natural log is as good as a quantitative one, so: My proof: Show by counter example: a = 1 b = x, 0<x<1 We know lnx is negative and ln1 = 0 by the properties of a logarithm. Thus, ln(a+b)...

So, I am guessing that hint entails: ab\geqa+b _______ I have two other ideas, but I have tried every combination of them to get them both to be true... Nothing I try seems make it work. I am thinking that the ln(ab) and ln(a+b) have to not be irrational for this to be a valid proof? Is my...

Homework Statement Show that the natural logarithm is not subadditive. You could use ln(1/2+1/3)\leqln(1/2)+ln(1/3), but mathematicians view all such numerical evidence as an invalid proof. Homework Equations ln(a+b)\leqln(a)+ln(b)The Attempt at a Solution ln(1/2+1/2)\leqln(1/2)+ln(1/2) Well...

I am pretty sure Maxima is written in Lisp. I am not sure exactly how one gets involved in programming it.

Well I figured out b. Since one of the requirements of a field is that the multiplicative inverse is defined for all elements of the field. We can prove the triple (R2,+,\bullet) is not a field. As a side note the multiplicative identity of this non field is (1,0). Suppose (3,3)\inR2 has a...