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David Goodmanson


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David Goodmanson

639 total contributions since 2012

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Answered
Evaluating svd() on slice of matrix array.
Hi Morten I take it that your matrices are close to being orthonomal already. Try [Q, ~] = qr(A(:,:,i)); A(:,:,i) = Q; whic...

3 Tage ago | 0

Answered
How to solve a system of linear equations with strict inequalities and equalities?
Hi Terri, Looks like it is not possible. You have [F1;F2;F3] = [10 2 10 15 20 8 6 4 12] * [x1;...

3 Tage ago | 0

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Answered
How can I solve for the matrix S in the below mentioned matrix equation?
Hello NAA, It appears that you mean that d is 3x6,not 6x3. Let E = EPS_T - EPS_S and abbreviate inv(S) as iS. You are looki...

4 Tage ago | 1

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Answered
How do i scale to my axis after fft?
Hi Cherie, you have a time array of length, 601 and spacing deltat = .01. The frequency array is going to be 601 points with t...

5 Tage ago | 1

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Answered
Raise the elements of a matrix to a power.
Hi Ricardo, min3 = min.^3 It's not a good idea to name a variable 'min' because that is the name of a built-in Matlab function...

5 Tage ago | 1

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Answered
Solving an equation with terms that require double summation and products
Hi GS, I reproduced your results and then calculated the equation using for loops, just to make sure, and got 1.8767e37, same a...

5 Tage ago | 0

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Answered
Solving an equation with terms that require double summation and products
Hi GS, try aij_2 = aij.^2 Since y1 and y2 are scalars, there are three dots in the last equation that you can drop. I usuall...

6 Tage ago | 0

Answered
How to plot double sided amplitude spectrum after FFT?
Hi Hamid, at the end of your code I added the following: figure(2) plot(f,fftshift(cmag),'o'); grid on xlim([-30 30]); f...

7 Tage ago | 0

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Answered
Why are the symbolic units not evaluated by a square root?
Hi Lucas, try your original code but with the last two lines omega_n = (pi/l)^2*(g*E*I/(A*lambda))^(1/2) omega_n = vpa(simpli...

13 Tage ago | 0

Answered
how to calculate direction in rotated coordinate system
Hi UWM, Assuming the correct rotation has already been made, then calling the resulting vector u, and making sure it is normali...

13 Tage ago | 0

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Answered
Why did i get different answers for eigenvectors for different powers of a matrix?
Hi RMT, Since you have two identical eigenvalues, the eigenvectors corresponding to those eigenvalues are not unique*. They on...

13 Tage ago | 1

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Answered
Element-Wise Vector Division
HI Mark, new_vector = K./vector; ./ (dot divide) does element-by-element operations.

17 Tage ago | 1

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Answered
Vectorizing the addition of a vector of values with associated indices to an existing vector, when the vector of indices has repeated values.
Hi Nathan, sparse matrices automatically do what you want. You have full matrices, and sparse operations are on the slow side ...

17 Tage ago | 0

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Answered
Sub-sampling the minimum number of points to accurately reproduce a curve
Hi Michael, take a look at the interp1 function. There are several choices for the type of interpolation, and assuming a curve ...

17 Tage ago | 0

Answered
Cannot find ALL solutions to simultaneous equation
Hi CZ If exp(x^2+y^2+z^2) = 9 then x^2+y^2+z^2 = log(9) which is a lot less challenging for symbolic evaluation. clear all...

17 Tage ago | 0

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Answered
Troubles assigning colorbar values in a bivariate histogram plot
Hi Mar, I have been looking at this with some data I made up, but now that you posted it I was able to plug it in. I thought y...

18 Tage ago | 0

Answered
What to use instead of simple function?
Hi Liliana, 1/(2*pi^(1/2)*(1/(4*a^2))^(1/2)) may not be pretty, but it does equal a/sqrt(pi) so it is mathematically correct....

27 Tage ago | 0

Answered
a Simple Matrix question
Hello LC Matrix_C = matrix_A; Matrix_C(matrix_A == Matrix_B) = 255;

30 Tage ago | 0

Answered
How can I get more than 49 digits of pi in a string?
Hi India, vpa(pi,100) for example (although you need the symbolic toolbox for vpa) And see Walter's comment below. The answer...

etwa ein Monat ago | 0

Answered
plot polygon function error
Hi msh, the reason is pretty simple. You are asking for an output from the function, but you have not provided any in its defi...

etwa ein Monat ago | 0

Answered
why the legend show wrong lines ?
Hi tomer, try replacing plot(t,43*(19.6e-3)/(100*15e-3),' black '); %% plot--> of boundery limit with plot(t,43*(19.6e-3)/(...

etwa ein Monat ago | 0

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Answered
Solving 3 Simultaneous Exponential Equations
HI Rory, just for completeness y1 = 159.2543; y2 = 117.2699; y3 = 63.8384; x1 = 291.15; x2 = 293.15; x3 = 299.15; A1 =...

etwa ein Monat ago | 1

Answered
solve on vector equation
Hi Michiel, The unit vector N has to lie in the plane defined by s1 and s2. The result for any s1,s2 is N = s2 - (n1/n2)*s1;...

etwa ein Monat ago | 0

Answered
how can I creat a matrix of all possible combinations of zero and ones across eight digits.
HI Yonatan, not a black box: function a = x10(ndigits) a = ['0';'1']; count = 1; while count < ndigits n = size(...

etwa ein Monat ago | 0

Answered
IFFT of Convolution equivalence
Hi JOB/Ridwan Here is a small example where a and b are padded with zeros, so that regular convolution can be compared with con...

etwa ein Monat ago | 1

Answered
Why 999^999-999^999 is NaN?
HI Fahmy, >> realmax ans = 1.7977e+308 That's the largest floating point number in Mallab, which uses IEEE754 64 bit double ...

etwa ein Monat ago | 0

Answered
How to obtain CDF from the below PDF function
Hello Manesf, This pdf seems related to the Weibull distribution. I made some abrreviations Etta_d = xid Etta_D = xiD ...

etwa ein Monat ago | 1

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Answered
In the matlab page of Associated Legendre Polynomials, is the example for the spherical harmonics correct?
Hi chaitanya, Good catch. Really good catch. In addition to the signs of the lobes, I believe that Matlab's Y32 is functional...

etwa 2 Monate ago | 2

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Answered
How to plot the velocity of a crate on a ramp for different angles?
Hi Kiera, The plot above shows the velocity of the box at the top of the ramp getting larger as the angle of the ramp gets stee...

etwa 2 Monate ago | 0

Answered
associated legendre functions matlab
Hi chaitanya, It's apples and oranges. When the domain of the argument is -1 <= x <= 1, the function is -sqrt(1-x^2). That's ...

etwa 2 Monate ago | 0

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