Community Profile # David Goodmanson

### David Goodmanson

Last seen: Today 2012 이후 활성

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calculation code of PSD using fft
Hi DK, Since you are after power spectral density, and not the spectrum of the linear quantity fft(x), this means the square of...

4일 전 | 0

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precision of double variables
Hi Arda, you pretty much answered the question by mentioning precision. Most floating point numbers are not represented exactl...

10일 전 | 1

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My code is giving only one solution to a function although there are two solutions, what can I do to get all the solutions?
Hi JN, syms x; assume(x,'positive') and proceed as before for the second one. It is not a great idea to use 'roots' as the n...

11일 전 | 1

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plotting T-U diagram using XSteam
Hi Aldan, the code is running through all the values, but it's not saving any of them. You need to do something like m = 220;...

12일 전 | 0

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I want to highlight the curve of intersection of the sphare and the plane x+y+z=0 by a thick blue curve. How to do that?
Hi Atom, Your code doesn't work because if you multiply out X2^2 + Y2^2 + Z2^2, you don't get R^2. So that arc is not on the s...

16일 전 | 0

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How can I change this explicit method code to the implicit method code?
Hi MC I am not sure what is meant by 'implicit method', and while numerical methods are good, there is also the exact expressio...

19일 전 | 0

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How to plot the magnitude and the phase of this function f(1/z)=(0.5 + 000i)*z^(−1 )+ (0.2500 − 0.4330i)*z^(−2) + (−0.2500 − 0.4330i)*z^(−3)?
Hello Aisha, technically this equation should read f(z)=(0.5 + 000i)*z.^(−1 )+ (0.2500 − 0.4330i)*z.^(−2) + (−0.2500 − 0.4330i...

약 1달 전 | 0

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How to Plot Ramsey Phase Plane
HI ec, There are a couple of issues here. First, the cdot expression lacks a dot, should be k.^(alpha-1). Second, the grid ...

약 1달 전 | 0

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How the plot of the phase of the complex function look likes BY USING THE MATLAB?
Hi Aisha, Taking the second part first, a phase angle can be either positive or negative. The Matlab angle function uses the u...

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Analytical solution for 1D heat equation
Hi Dominick, you have the sum of two sine terms for the boundary condition, sin(x) and (1/10) sin(10x). So consider a general ...

약 2달 전 | 0

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Why is 0 and 30 1/2?
Hi Alexander; This occurs because heaviside(-.3:.1:.3) ans = 0 0 0 0.5000 1.0000 1.0000 1.0000 ...

약 2달 전 | 0

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Difference between numerical and analytical solution of ode?
Hi IG, Here is an almost-analytical solution for x0 and x1 (which are called x and y respectively). It's analytic for x, uses ...

2달 전 | 0

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I want to plot an implicit equation
Hi mohd, This is not really an implicit equation since Vgs appears only once, by itself, on the lhs. So you can take all the o...

2달 전 | 1

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Circular Cross Correlation 2D Using FFT
Hi Ziv, yes, it works similarly. m = 5; n = 6; q = 4; A = randi(m,n,q); B = randi(m,n,q); C = zeros(size(A)); for j = 1:...

2달 전 | 0

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How to get coefficients for second degree polynomial with only two given boundary conditions (means with two equations but with three coefficients)?
Hi Ankit, x = [ 0 1 2 3]; E = [0 1 4.5 10.5]; c = polyfit(x,E,2) % fit a quadratic E1 = polyval(c,x) figure(1) plot(x,...

3달 전 | 0

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Is there any way to plot values that are exponent multiples of 10 as colorbar directly without having to take their log
Hi Mathan, The colorbars cover the same range in each case, but It's still apples and oranges. Consider the value 1e6 In log sp...

3달 전 | 1

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Can anyone help me? How can I solve 4th order Ordinary differential equations (ODEs)?
Hi Jihweon, Fortunately the analytic solution is pretty straightforward. Denoting Sp by A, the A^-4 factor matches up with the...

3달 전 | 1

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Getting complex value for real integration
Hi Mithun, One of the more straightforward methods is to forget about symbolics and just write down the solution for y. The el...

3달 전 | 0

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finding the maxima/minima using lagrange mutlipliers
Hi Ikenna, Here is one way. If you plot the function on the ellipse th = linspace(0,2*pi,1000); xx = cos(th); yy = sin(th)/...

3달 전 | 0

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Unitary matrix with non-orthogonal eigenvectors?
Hi Joshua, I believe this happens because W has at least one set of degenerate eigenvalues, and does not happen if all the eige...

3달 전 | 0

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Complex output after applying inverse fourier transform
Hi Brian, I beleive the result is due to asymmetric truncation of the image in the frequency domain. I am inferring that your ...

3달 전 | 0

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Split array into subarrays
Hi David, if A is 200x1 the easiest way to do that is B = reshape(A,50,4) so now B is a matrix whose four columns are each 50...

3달 전 | 1

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How solve this problem in Matlab
Hi Davide, here is a method that uses one for loop instead of two: n = 5 m = 6 V = zeros(n,m); V(:,1) = 1:n; for k = 2:m ...

3달 전 | 0

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trigonometric equation solution help
Hi Giuseppe Although Matlab can't come up with an analytic solution with symbolics, you can still obtain a numerical solution t...

3달 전 | 0

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Efficient way of performing operation on array after performing cumsum
Hi Valentina, A = [1 2 3; 4 5 6; 7 8 9]; B = cumsum(A,2); C = (1:3).\B This gives the result that you show in your question....

3달 전 | 1

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Finding peak value of distorted sine wave signal with varying phase shift of harmonics
Hello Haroon, This answer addresses the first part, getting a maximum or "minimum-at-maximum" value. It's a lot easier to do t...

3달 전 | 0

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How to use syms to solve system of equations?
Hi NIcholas, This can be done without using syms. Syms of course can be slow, and the result in this case is a typically ponde...

3달 전 | 2

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How can I obtain the analytical expression (polynomial) of the spline curve from a curve fitting?
Hi Radu, x = 1:10; y = sin(x).^3; a = interp1(x,y,'spline','pp') a = struct with fields: form: 'pp' br...

4달 전 | 0

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sum of a sum of a sum of a sum
Hi Marta, The code below does not address the algebra in the paper, but I am posting this because it is another way of doing th...

4달 전 | 1

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How can I define proper frequency domain of FFT function in Matlab
Probably a bit late in the game, but the followiing code shows the peak at 300Thz. A couple of issues here: first to (a) get a...

4달 전 | 0