Answered

Fourier series of any function

Hello Danny, the problem is that you are supposed to approximate the function with a sum of sines and cosines with certain ampl...

Fourier series of any function

Hello Danny, the problem is that you are supposed to approximate the function with a sum of sines and cosines with certain ampl...

2 days ago | 0

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Answered

Order of integration in double integral

Hi A.K. If you are convinced that the problem arises from the square root singularity, one approach is a change of variable y ...

Order of integration in double integral

Hi A.K. If you are convinced that the problem arises from the square root singularity, one approach is a change of variable y ...

2 days ago | 0

Answered

How to integrate products of hypergeometric functions and rational functions?

Hello Nicolas, I don't know how you are implementing the nth derivative of 1/(lambda^2 + q^2) but it is obviously very time con...

How to integrate products of hypergeometric functions and rational functions?

Hello Nicolas, I don't know how you are implementing the nth derivative of 1/(lambda^2 + q^2) but it is obviously very time con...

3 days ago | 0

| accepted

Answered

Simplifying a complex function in order to separate real and imaginary part?

Hi zah ra, An explicit form for real and imaginary parts of (1 - r*exp(theta*1i))^(3/2) is possible, although not particularl...

Simplifying a complex function in order to separate real and imaginary part?

Hi zah ra, An explicit form for real and imaginary parts of (1 - r*exp(theta*1i))^(3/2) is possible, although not particularl...

7 days ago | 0

Answered

Steady-states and non-trivial eigenvalues of equation

Hi katara, the fixed points are at 0,theta,K as you said. Although you don't have specific values, the derivatives, which you ...

Steady-states and non-trivial eigenvalues of equation

Hi katara, the fixed points are at 0,theta,K as you said. Although you don't have specific values, the derivatives, which you ...

8 days ago | 0

Answered

Cannot use besselh as function handle

Hi wbriand, any reason you can't just define F = @(nu,z) besselh(nu,1,z) or F = @(nu,z) besselh(nu,2,z) whichever one you w...

Cannot use besselh as function handle

Hi wbriand, any reason you can't just define F = @(nu,z) besselh(nu,1,z) or F = @(nu,z) besselh(nu,2,z) whichever one you w...

8 days ago | 0

Answered

Scaling an array by a certain number so that the area under the curve equals a fixed number

HI Christina, A = trapz(x,pyy) % find the unscaled area pyy_new = pyy*(30/A); trapz(x,pyy_new) % this ...

Scaling an array by a certain number so that the area under the curve equals a fixed number

HI Christina, A = trapz(x,pyy) % find the unscaled area pyy_new = pyy*(30/A); trapz(x,pyy_new) % this ...

15 days ago | 0

Answered

ilaplace() function is giving wrong results

Hi David, plugging in cosh(z) = ((exp(z) + exp(-z))/2 sinh(z) = ((exp(z) - exp(-z))/2 results in a constant and two exponent...

ilaplace() function is giving wrong results

Hi David, plugging in cosh(z) = ((exp(z) + exp(-z))/2 sinh(z) = ((exp(z) - exp(-z))/2 results in a constant and two exponent...

16 days ago | 0

Answered

clamp cross-entropy loss

Hi Matt, z = log(Y); z(z<100) = 100; loss = -sum(W*(T.*z))/N; In the link you provided, they talk about a limit of -100 rath...

clamp cross-entropy loss

Hi Matt, z = log(Y); z(z<100) = 100; loss = -sum(W*(T.*z))/N; In the link you provided, they talk about a limit of -100 rath...

16 days ago | 0

| accepted

Answered

Vectorization time-varying recursive linear function

Hi Bruno, a = rand(1,50); b = rand(1,50); % method 1 xk = 0; x = zeros(1,50); for k = 1:50 xk = a(k)*xk + b(k); ...

Vectorization time-varying recursive linear function

Hi Bruno, a = rand(1,50); b = rand(1,50); % method 1 xk = 0; x = zeros(1,50); for k = 1:50 xk = a(k)*xk + b(k); ...

22 days ago | 0

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Answered

Laplace of heaviside function with negative arguments

Hi Darius, since the laplace transform is Integral{0,inf} f(t)*exp(-s*t) dt, the value of f(t) for t<0 makes no difference. ...

Laplace of heaviside function with negative arguments

Hi Darius, since the laplace transform is Integral{0,inf} f(t)*exp(-s*t) dt, the value of f(t) for t<0 makes no difference. ...

24 days ago | 0

Answered

Intersection line and quadrilateral

Hi Francesco Here is one way. The function linecross determines whether two line segments intersect. The function yesno just ...

Intersection line and quadrilateral

Hi Francesco Here is one way. The function linecross determines whether two line segments intersect. The function yesno just ...

1 month ago | 0

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Answered

How to find out the intersection points between two 3D ellipsoids?

Hi PA, As has been alluded to, the intersection of these two surfaces results in lines. These are calculated below. The abc c...

How to find out the intersection points between two 3D ellipsoids?

Hi PA, As has been alluded to, the intersection of these two surfaces results in lines. These are calculated below. The abc c...

1 month ago | 0

Answered

dot multiplication of the matrices is not the same when you feed the matrix and concatenate the matrix

Hi mohammed, For H1_2 you have switched a3 and a4 between the first calculation and the hand calculation. So you get two diffe...

dot multiplication of the matrices is not the same when you feed the matrix and concatenate the matrix

Hi mohammed, For H1_2 you have switched a3 and a4 between the first calculation and the hand calculation. So you get two diffe...

1 month ago | 0

Answered

About FFT of cosine function

Hi mk, In order to get just the two sharp peaks you need to have exactly n oscillations in the time domain. Otherwise the wave...

About FFT of cosine function

Hi mk, In order to get just the two sharp peaks you need to have exactly n oscillations in the time domain. Otherwise the wave...

1 month ago | 0

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Answered

impulse response for difference equation

Hi Roger, try bb(N+1) = -power(a,N); which is what you actually have. I think you'll lilke the resulting plot.

impulse response for difference equation

Hi Roger, try bb(N+1) = -power(a,N); which is what you actually have. I think you'll lilke the resulting plot.

2 months ago | 0

| accepted

Answered

How can I solve this set of complex equations?

Hi Stefanos, As has already been mentioned, the 4th equation is just the definition of V0' and is independent of the first thre...

How can I solve this set of complex equations?

Hi Stefanos, As has already been mentioned, the 4th equation is just the definition of V0' and is independent of the first thre...

2 months ago | 0

Answered

Changing a parameter in a differential equation?

Hi Sean, you can pass the value of epsilon into the ode function with [tSol,YSol]=ode45(@(t,Y) quantumsystem(t,Y,epsilon),tRan...

Changing a parameter in a differential equation?

Hi Sean, you can pass the value of epsilon into the ode function with [tSol,YSol]=ode45(@(t,Y) quantumsystem(t,Y,epsilon),tRan...

2 months ago | 0

| accepted

Answered

Regularized hypergeometric function 1F2 within matlab?

Hi Wozciech, if you add a prod function, part3 = prod(gamma([(1-n/2),(3/2 - n/2)])) then you're good to go. Or, you could us...

Regularized hypergeometric function 1F2 within matlab?

Hi Wozciech, if you add a prod function, part3 = prod(gamma([(1-n/2),(3/2 - n/2)])) then you're good to go. Or, you could us...

2 months ago | 1

| accepted

Answered

Matrix multiplied by inverse is not giving correct answer

Matlab is telling you the answer, that the matrix (call it M) is close to singular or badly scaled (singular in this case). M h...

Matrix multiplied by inverse is not giving correct answer

Matlab is telling you the answer, that the matrix (call it M) is close to singular or badly scaled (singular in this case). M h...

2 months ago | 1

Answered

Complex number and fft

Hi Nmak, you are just getting into standard numerical precision issues. The fft and ifft involove complex variable calculation...

Complex number and fft

Hi Nmak, you are just getting into standard numerical precision issues. The fft and ifft involove complex variable calculation...

2 months ago | 1

| accepted

Answered

Interpolating and resampling around closed curve to calculate centroid

Hi Sofia, Since your points are pretty closely spaced, there is not much need to interpolate the points. The method below pick...

Interpolating and resampling around closed curve to calculate centroid

Hi Sofia, Since your points are pretty closely spaced, there is not much need to interpolate the points. The method below pick...

2 months ago | 1

| accepted

Answered

Regularizied hypergeometric function gives an error for z being greater than 1.

Hi Wojciech, I am assuming that there is no problem when n is not an integer, only when n is a positive integer greater than 1....

Regularizied hypergeometric function gives an error for z being greater than 1.

Hi Wojciech, I am assuming that there is no problem when n is not an integer, only when n is a positive integer greater than 1....

2 months ago | 1

| accepted

Answered

Smooth derivative of a matrix

Hi Daniel As you know, multiplying each column of a unitary matrix by a scalar phase factor still results in a unitary matrix (...

Smooth derivative of a matrix

Hi Daniel As you know, multiplying each column of a unitary matrix by a scalar phase factor still results in a unitary matrix (...

2 months ago | 1

Answered

solve and plot nonlinear system of equations with no explicit solution

HI Cengizhan, MODIFIED The first equation above is (-1/2)*(cos(x)*cos(z)+sin(theta)/psi) = 0 (1) which has an extraneous ...

solve and plot nonlinear system of equations with no explicit solution

HI Cengizhan, MODIFIED The first equation above is (-1/2)*(cos(x)*cos(z)+sin(theta)/psi) = 0 (1) which has an extraneous ...

2 months ago | 0

Answered

Check whether the symbolic eigen value of a matrix is positive or negative

Hello TS with your definition of Am we have simplify(trace(Am)) ans = -(672*d*g + a*d^4 + 36*a*g^2 + 576*g^2 + 42*a*d*g + ...

Check whether the symbolic eigen value of a matrix is positive or negative

Hello TS with your definition of Am we have simplify(trace(Am)) ans = -(672*d*g + a*d^4 + 36*a*g^2 + 576*g^2 + 42*a*d*g + ...

2 months ago | 1

| accepted

Answered

Large integer rounding problem

Hello HS, you ran into the limits of double precision numbers. However, (1+x/n)^n = e^x*f % f = correction factor...

Large integer rounding problem

Hello HS, you ran into the limits of double precision numbers. However, (1+x/n)^n = e^x*f % f = correction factor...

2 months ago | 0

| accepted

Answered

Remove peak at 0 hz of fft

Hi Emmy It's all in how you view things. Literally. Here is what happens when using x - mean(x). fs = 1000; N = 30000; fig...

Remove peak at 0 hz of fft

Hi Emmy It's all in how you view things. Literally. Here is what happens when using x - mean(x). fs = 1000; N = 30000; fig...

2 months ago | 0

| accepted

Answered

Using 'solve' on a vector of line equations?

Hi Jonathan, It's not totally clear if the geometry is such that there is a separate t value for each row of the hits{1} and hi...

Using 'solve' on a vector of line equations?

Hi Jonathan, It's not totally clear if the geometry is such that there is a separate t value for each row of the hits{1} and hi...

2 months ago | 1

| accepted

Answered

Calculating the contributing terms of a summation equation

Hi Bharath, suppose the sum involving q is done over a dummy index j instead of i. It appears that Y and y are vectors of the ...

Calculating the contributing terms of a summation equation

Hi Bharath, suppose the sum involving q is done over a dummy index j instead of i. It appears that Y and y are vectors of the ...

3 months ago | 0