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David Goodmanson

David Goodmanson

Last seen: Today Active since 2012

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Recurrence relation for polynomial indices
Hello Jaime, Suppose you want the results up to a polynomial of degree p. The following code creates a (p+1)x(p+1) matrix c of...

10 hours ago | 0

How can I represent the sparse mass, damping and stiffness matrices in state space?
HI 'M', Suppose you have n positions and n corresponding velocities. Let the state space (column) vector be in the order y = ...

1 day ago | 0

Adding matrices (to assemble global stiffness matrix)
Hi Ryan, here is an example. In the code below, a and b are the indices of the 4x4 submatrix of K that each stiffness submatri...

9 days ago | 0

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Hello Matthew, this is happening because the image uses uint8 values (unsigned integer 8 bit), with a range of 0 to 2^8 -1 = 25...

10 days ago | 0

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How to calculate energy of the signal at a specific frequency after applying FFT
Hello Daniel, To get the desired result you have to be careful about the number of points, so that an exact number of oscillati...

13 days ago | 0

How to multiply each column in the matrix by different scientific notation values that should be imported from a txt file?
HI Gabrielle, MODIFIED Looks like you have constructing the 128x256 matrix of values covered. The code below converts S{1} to...

14 days ago | 0

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Using numerical methods to plot solution to first-order nonlinear differential equation
Hello Aleem, You are saying that the analytical solution is not relevant because it involves complex numbers, but that's not th...

14 days ago | 0

MATLAB determine if matrices are invertible or not
Hi SS P+Q ans = 9 9 2 13 0 0 3 4 -3 -3 6 1 1 1 2 6 det(P+Q) ans = ...

15 days ago | 1

Solve matrix series equation
Hi Ramesh, This is an overdetermined system, but if you define x as a 2x7 matrix of 2d coordinate values and X as a correspondi...

17 days ago | 0

interpreting frequency vs phase plot in fft
Hello JL, Since sin(2*pi*f*t) = ( e^(2*pi*i*f*t)-e^(-2*pi*i*f*t) )/(2i), (1) the sine signal has both positive and ...

20 days ago | 0

Why does the cscvn function of matlab have 4*2*(n-1) coefficients?
Hello Ashkan, factor of (n-1) because n points --> (n-1) intervals, and the polynomials are defined on the intervals factor o...

23 days ago | 0

Solving a transcendental equation
Hi Kubilay, Finding an algebraic solution for this equation in terms of lambda is not going to happen. But a numerical solutio...

28 days ago | 1

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How to use Poisson distribution?
Hi Jaya, You appear to be saying that you can't use a loop to increment through event times. For example, though, just before ...

30 days ago | 0

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I want to treat w as a constant
Hello HJ, try replacing the first line with syms y(x) w real in which case the result is ySol(x) = (exp(-x)*(sin(w*x) + w*c...

1 month ago | 0

Setting a 3rd vector with specific angles to 2 other vectors
Hi Huseyin, The method you are using gets you into an iterative process of successive rotations about the x and z axis that eve...

1 month ago | 0

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ODE system with 2 degrees of freedom
Hi Nader, you only need four variables, theta1, theta1dot, theta2, theta2dot (not six). Try function dydt = ODEsystem(t,y) k...

1 month ago | 1

How to prove the positivity if this function?
Hi Andrea, What might constitute a proof using Matlab is a good question. If the answer to isAlways(y>=0) had come out as 1, w...

1 month ago | 0

fixing of random number
Hi Irani, If I understand your question correctly, rng(1) Y = randi(10) rng('shuffle') node = randi(20) gives the same val...

1 month ago | 0

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how to find the angle subtended from origin to the poles in complex plane?
Hello Muhammed, it's as easy as angle(65+65j) angle(65-65j) with each angle in radians subtended from the x axis, -pi < angl...

2 months ago | 0

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Matlab and Fortran Precision Issue
Hello SA It's the constants. First of all for simplicity I commented out everythng not concerned with calculation of ORIGINAL_...

2 months ago | 0

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How do you inverse fourier transform 2D data only in one direction?
Hi Gabrielle, I'm not exactly sure what is meant by 'in the x direction' but it sounds like dimension 2. Anyway, ifft(Y,[],2)...

2 months ago | 0

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Principal Component Analysis: difference between V matrix from SVD decomposition and coef from pca?
Hello Jessica, The set of column vectors that define V in svd, or define coeff in pca, can differ from each other by a factor o...

2 months ago | 0

extract roll pitch yaw rotation angles from 3D transform
Hello "AT" fwiw, here is a version of finding three rotation angles th1,th2,th3 from a 3d rotation matrix defined below. Ang...

2 months ago | 0

my question is what is wrong with my code, the results should be in the first picture not the second.
Hi jana, the problem is that the if statements if mod(row,2)==0 && mod(col,2) ==1 && col>=3 % (b) and i...

2 months ago | 0

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My solver is giving extremely large numbers for a straight forward system of linear equations, what's wrong?
Hi John, What the solver is trying to tell you is that a solution does not exist for this problem, or more correctly it exists ...

2 months ago | 1

Finding Argument of Bessel Function (1st Kind) to Return Known Solution
Hello 1:5, syms r ex = 5; R = 160; F = besselj(0,(2.405*r)/(R + ex)); Ratio = 0.3005; q = F == Ratio; vpasolve(q,r,[0 ...

2 months ago | 0

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Multiplication of sparse matrix and a normal matrix
Hi Amit, sum(S)' where the result is still sparse, or full(sum(S)') if you want a regular vector at that point.

2 months ago | 0

How to find the best fit curve as a vertical scaling of another curve?
Hi SojM, Suppose you have points x,y for the function f(x), where x and y are column vectors. And suppose the red points are t...

2 months ago | 0

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Solving a system of 4 equations to find the cosine directions from stress matrix and principle stress
Hi Trevor, After taking the terms involving sigma over to the right hand side, the equations are just the eigenvalue equation w...

2 months ago | 0

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