Risposto

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 ...

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 ...

7 mesi fa | 1

| accettato

Risposto

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...

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...

7 mesi fa | 1

Risposto

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...

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...

7 mesi fa | 2

| accettato

Risposto

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...

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...

7 mesi fa | 0

| accettato

Risposto

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. ...

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. ...

8 mesi fa | 0

Risposto

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...

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...

8 mesi fa | 2

Risposto

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...

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...

8 mesi fa | 0

| accettato

Risposto

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 ...

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 ...

9 mesi fa | 1

Risposto

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...

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...

9 mesi fa | 0

| accettato

Risposto

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 ...

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 ...

9 mesi fa | 0

Risposto

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...

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...

10 mesi fa | 1

| accettato

Risposto

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 ...

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 ...

11 mesi fa | 0

Risposto

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...

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...

circa un anno fa | 0

Risposto

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...

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...

circa un anno fa | 0

Risposto

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...

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...

circa un anno fa | 0

Risposto

calculation error in hyperbolic function

one possibility: (tanh(-10))^2 ans = 1.0000 % correct although tanh(-(10)^2) % traveling parenthesis ans =...

calculation error in hyperbolic function

one possibility: (tanh(-10))^2 ans = 1.0000 % correct although tanh(-(10)^2) % traveling parenthesis ans =...

circa un anno fa | 0

Risposto

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.

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.

circa un anno fa | 1

Risposto

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...

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...

circa un anno fa | 0

Risposto

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...

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...

circa un anno fa | 2

| accettato

Risposto

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...

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...

circa un anno fa | 0

Risposto

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...

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...

circa un anno fa | 1

| accettato

Risposto

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...

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...

circa un anno fa | 0

Risposto

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 ...

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 ...

circa un anno fa | 0

| accettato

Risposto

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...

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...

circa un anno fa | 0

| accettato

Risposto

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 ...

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 ...

circa un anno fa | 0

Risposto

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...

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...

circa un anno fa | 1

Risposto

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 ...

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 ...

circa un anno fa | 1

Risposto

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 ...

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 ...

circa un anno fa | 0

Risposto

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...

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...

circa un anno fa | 0

| accettato

Risposto

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...

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...

circa un anno fa | 0