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David Goodmanson


Last seen: Today |  Active since 2012

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Answered
No feasible solution found
Hi Preston, It seems likely that this is a planar structure with the diagonal elements having length sqrt(2). (If all th...

14 days ago | 0

Answered
2D Fourier transform- problems with the shift
Hi nathan, It is a bit more inconvenent but you can reconstruct using a shifted grid as you did. I kept that method in in the ...

20 days ago | 0

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Answered
How to find indices of resampled values from the indices of the original values?
Hello Mibang, Rather than snew = resample(s,fsnew,fs) I think it's safer to use [snew tnew] = resample(s,t,fsnew) because t...

26 days ago | 1

Answered
fft and ifft of signal seem to cause time reversal
Hi sgreess, I'm guessing your input signal is a column vector. In that case the command spectra = spectra' by Matlab conven...

29 days ago | 0

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Answered
How to fit this model with a Weibull distribution?
Hi MIchele, One possibility is that you are not fitting the correct statistical function to the data. The algebraic expression...

2 months ago | 0

Answered
Problem with integration: there is a pole on a contour
Hi SB You can use the principal value for the integration,which is defined as (1/2) * [ (integral with path on one side of the...

2 months ago | 1

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Answered
Generalised solution to a n-order system of equations
HI Aden, Here is a method that produces, within 4.5 %, the experimental value a_1 = 2.518. The equation is (for simplicty n-1 ...

2 months ago | 1

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Answered
Solve more complex problems in matlab
HI OF, y(x) = (m-2)x^2 -3mx + (m+2) The domain of m where the two roots have opposite sign is a numerical question and I think...

3 months ago | 0

Answered
How can I scale and plot the graph according to the formula I use?
Hi Zaref, One thing for sure about eq.(19) in the attachment is that eps0 can't be in the numerator. eps_m is dimensionless (a...

3 months ago | 0

Answered
Plotting Complex Functions.
Hello Sudharsana, Do you mean f(t) = exp(-ar/(twC))*exp(-ai/(twC)) or f(t) = exp(-ar/(twC))*exp(-i*ai/(twC)) ...

3 months ago | 0

Answered
How to apply orientation constraints between two rigid bodies
Hi Aiden, because of the parallelism there are only two degrees of freedom here (assuming that one pivot point is the hole nea...

3 months ago | 1

Answered
How to generate white noise signal from a given PSD?
One can just create the desired waveform that has psd = S0 without resorting to S/N. The example below has a crazy large unphys...

3 months ago | 0

Answered
How can I replace the upper off diagonal(super diagonal) and lower off diagonal(sub diagonal) of a matrix?
Hello Olawale m = rand(5,5) m1 = diag(m,1) % original upper diagonal a = [2 3 4 5]' % new upper diagonal elements mn...

3 months ago | 1

Answered
double and triple integral for a complex function. I coded but did not get any output
Hi Orpita, Here is a way to at least reduce the dimension of the integral from 5d to 3d. First of all, the quantity (x+1/2) se...

4 months ago | 0

Answered
Logarithmic trendline equation of data
Hello Cem, As has been mentioned you can use the curve fitting toolbox for this job, but if you don't have it you can try a sim...

4 months ago | 0

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Answered
How change two columns with 5 rows to a single row?
Hi Bajdar, xy = [x; y]; z = xy(:)' i.e. concatenate x and y vertically, read that matrix out columnwise, then take the transp...

4 months ago | 0

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Answered
Hi, I am applying findpeaks function to find the peaks of an oscilloscope signal but in the peak plot graph it is automatically changing the x-label with a large difference.
Hi Rikita, if you use findpeaks(y,x) where x is the x axis (linear or log scale) whose min and max match the oscilloscope trace ...

4 months ago | 0

Answered
Why such a fuss with ndgrid and meshgrid issues?
Hi Kristoffer, I totally agree that Mathworks should use nonsquare examples in the documentation for meshgrid, ndgrid, surf etc...

5 months ago | 1

Answered
How do I find the phase for a periodic cos wave using fft?
Hi Noam, here is a version using time and frequency in the usual manner. A couple of ponts here. If you construct a grid as y...

5 months ago | 0

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Answered
how to write the right code to measure the elapsed time of this method d1 = diag(1./diag(A))
Hi Amna, A common way to do this is with tic and toc. So: a = rand(1e4,1e4); tic b = diag(1./diag(a)); toc Elapsed time...

5 months ago | 0

Answered
using polyval with one of the polynomials of a spline obtained with the unmkpp command, the results do not overlap! Why?
Hello TH,. spline polynomials are local to the secgment in question starting from x = 0, so if an interval is, for example 3 to...

5 months ago | 1

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Answered
Multiplication of submatrices of a matrix
Hi Laura, if I interpret this correctly, you have n rows (I'll use small letters mostly) of the form Anew = [c c*b1 c c*b2 ...

5 months ago | 0

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Answered
matrix inverse results different between r2023b and 2021b
Hi QL. you called both the inverse matrices '2021b' so I called the first one F and the second one S (and the orginal matrix is...

5 months ago | 0

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Answered
How do I get rid of these weird lines in the surf plot?
Hello Max, It appears that the GetRectGrid function creates points whose order is imcompatible with the reshape functions that ...

6 months ago | 1

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Answered
Error in ode45 solution
Hello PS, Assuming the following (before variables get changed around) tv_jk = tv_kj, for all j,k all real de...

6 months ago | 0

Answered
reproduces the audio signal after sampling!!!
Hello Vu & Paul, < I took a brief look at the Vaidyanathan.paper and although the decimation process seems clear enough, the 'i...

6 months ago | 1

Answered
Matlab got this wrong: Limit as n goes to infinity: (1+(i/n))^(n^2). Matlab says it's exp(2), which is wrong. Pls confirm.
Hi Moses, not every expression has a limit, or should. That's the case here, as anyone can check. For large n the function zi...

6 months ago | 1

Answered
Is there a way to create a lot of graphs for a 4D matrix without coding for a ton of individual graphs?
Hi Kitt, Here is one approach. In the example you are using imagsc plots instead of e.g. 1d plots of some state quantity vs. t...

7 months ago | 1

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Answered
How can I calculate the integral of associate LegendreP(1,n,theta)*cos(theta)^2 ?
Hello Se, First of all I think you probably mean the integral of P(1,n,cos(theta))*cos(theta)^2 which is what makes sense whe...

7 months ago | 0

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Answered
How to solve swallowtail integral
Hello YM, You won't be able to solve this as a closed form function of X,Y,Z but you can find the integral for given values of ...

7 months ago | 0

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