Answered
How can I create a random matrix without repeating any value between column
Hello Wan, all columns contain 1 through 4, and all columns are different a = perms(1:4) % all 24 permutations of 1:4 ...

11 months ago | 1

| accepted

Answered
recreating roots of a derivative of bessel funtion of first order
Hi fv, Here is a function for the first q zeros of both Jn(x) and dJn(x) /dx. As an example, to find the first 100 zeros of th...

11 months ago | 1

Answered
Picking Branch Cut of Square Root
Hi bil, Here is a function that does that job. It appears that you want to do the division (a-i)/(a+i) before taking the squar...

11 months ago | 2

| accepted

Answered
Find the nonzero maximum frequency corresponding to FFT graph.
Hi Zahra, the peak at zero frequency is because your signal does not have average value of zero, but has a DC offset. To elimi...

12 months ago | 0

| accepted

Answered
Find combination of 12 matrix rows, fulfilling certain criterion, from matrix of size 3432 *7
Hi Ernesto, Once you have a single 12x7 solution you can make many more by random element swapping of elements in that matrix. ...

12 months ago | 0

Answered
I know it is a redundant question, but i have no idea why solve keeps returning 0
Hello Andrei, First of all, all these expressions are functions of (x1-x2) and (y1-y2) only. That means if x1,x2,y1,y2 is a so...

1 year ago | 2

Answered
atanh of negative complex numbers
Hi Derek, For the troublesome subplot, try semilogx(f,unwrap(imag(2*x*gamma))/(2*x)) The idea is that the phase is proportion...

1 year ago | 0

| accepted

Answered
Solving systems of trig equations
Hi Jon, Here is one method. To come up with values of r and g that work, it appears to be easier to think in terms of R = r^2 ...

1 year ago | 1

Answered
Change the period/frequency of a Van der Pol Oscillator
Hi Alexis, If you want to preserve the shape you will have to have a larger set of parameters. I am taking as given your equa...

1 year ago | 0

| accepted

Answered
Cconditional subtraction of 2 vectors of different lengths
Hi salah, You can do quite a bit if the two vectors are sorted. Assume you have two sorted vectors sx and sy of length Nx and ...

1 year ago | 0

Answered
Get "Matrix is is singular to working precision" when attempting a global stiffness matrix with four nodes
Hi Declan, I am not sure how you are getting the error message. Running the code with k changed to K d(range) = K(range,range...

1 year ago | 1

| accepted

Answered
energy signal
Hi k.v. For a given real signal y(n) of length N, n = 1 to N, the power at any point n is y(n)^2, the average power P is Pave ...

1 year ago | 0

Answered
How can I evaluate a complex definite integral?
Hi Valentin, It's not strictly necessary (see Paul's vpa solution) but it is advantageous to scale things properly before doing...

1 year ago | 0

Answered
How to use sinc function
Hi Ricardo, while it might be nice to have the Signal Processing toolbox, you certainly don't need to buy any toolboxes to do t...

1 year ago | 0

| accepted

Answered
how to find concave angle between three points
Hi Eliska, One thing that does not seem to be mentioned so far is your use of the norm function on the determinant. That makes...

1 year ago | 0

Answered
calculation error in hyperbolic function
one possibility: (tanh(-10))^2 ans = 1.0000 % correct although tanh(-(10)^2) % traveling parenthesis ans =...

1 year ago | 0

Answered
Partial derivative with respect to x^2
Hi Yadavindu, df/d(x^2) = (df/dx) / (d(x^2)/dx) = (df/dx) / (2*x) which you can code up without the issue you are seeing.

1 year ago | 1

Answered
Solving a system of Non-linear Equations with Complex numbers
Hellol Aravindhan, not solved by Matlab, but a bit of algebra shows that with x(1) = 2000*a x(2) = 2000*b x(3) = theta/5 t...

1 year ago | 0

Answered
Increasing the caclulation speed while using loops
Hi Hamid, Hi Hamid, I have not speed checked this but it should be faster (the range in your example is different from the draw...

1 year ago | 2

| accepted

Answered
How to introduce a phase shift to a existing vector
I assume that you are given the oscillatory function V in an array, with no accompanying array for the independent variable to s...

1 year ago | 0

Answered
Average of random variables from two Poisson distributions?
Hi Jonne, I assume you want to look at the distribution for a period of one minute, whenever that might occur. As opposed to l...

1 year ago | 1

| accepted

Answered
How to extrapolate a plot?
What is being fitted is T vs. C, with the idea of extrapolating to T=0. The C variable, C=log((A0-A1)./(A-A1)) contains A, wh...

1 year ago | 0

Answered
z transfer function evaluates to inaccurate value near z=1
Hi Ashish, This function, ((1-1/z^2)/(1-1/z))^6 is identically equal to ((z+1)/z)^6 so you can just use that. And it does ...

1 year ago | 0

| accepted

Answered
Why am I getting wrong spectrum applying FFT comparing with correct spectrum?
Hi Jiang, There are a couple of things going on here. The expression for FFT is not correct. Since you are taking the real pa...

1 year ago | 0

| accepted

Answered
Solve system of equations with some knowns and unknowns in the same matrix
Hi Yusuf, I'm later on an answer (and losing the race more often, to the extent that there is a race, which to be honest there ...

1 year ago | 0

Answered
How can I code a contour integral representation of cosine?
Hi Richard, this integral converges very slowly along the vertical path gamma-i*inf to gamma+i*inf. Convergence depends on wha...

1 year ago | 1

Answered
reverse lookup table from vector multiplikation with unknown vectors
Hello Henning, Assuming that you want column vectors a and b such that their outer product C = a*b' is as close as possible to ...

1 year ago | 1

Answered
How to define color on matrix figure
Hi Jan, the following method comes up with black not just for values that are exactly zero (I don't know how likely that might ...

1 year ago | 0

Answered
Question using IFFT, try to transform continuous 1 from frequency in time domain
Hi Jan, In the secnd example the dirac value should be quite large, In fact it should be 3e5, the number of points, not half o...

1 year ago | 0

| accepted

Answered
fminsearch for a function f(x,y) = x^4 -3xy+2y^2
Hi Ibraheem, While it's useful to find out about how to get fminsearch to cooperate, that's hardly necessary here. For the min...

1 year ago | 0