Community Profile

photo

David Goodmanson


Last seen: Today

David Goodmanson

767 2012 이후 총 참여 횟수

담당자

David Goodmanson's 배지

  • 24 Month Streak
  • Guiding Light
  • Revival Level 2
  • Knowledgeable Level 4
  • First Answer
  • Solver

세부 정보 보기...

참여 게시물
보기 기준

답변 있음
solve and plot nonlinear system of equations with no explicit solution
HI Cengizhan, Software has not quite taken over yet, athough it's closing in. If you start dividing equations by hand(!) and s...

약 6시간 전 | 0

답변 있음
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 + ...

1일 전 | 1

| 수락됨

답변 있음
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...

2일 전 | 0

| 수락됨

답변 있음
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...

7일 전 | 0

| 수락됨

답변 있음
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...

9일 전 | 1

| 수락됨

답변 있음
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 ...

11일 전 | 0

답변 있음
use the previous result of a function in the calculation
Hi Matthew, there is definitely a better way. Y = filter(B,[1 -A],X) Here the assumption is that X is an input vector and B i...

14일 전 | 0

답변 있음
Plotting Fourier series from fft output / how to obtain fundamental freq.
Hi Morgan, In this situation with periodic waves, the ftt is divided by L, as you have. The fft is at heart an operation using...

19일 전 | 0

답변 있음
quintuple summation using a for loop
Hello Wyatt, The sum comes out zero because it is, in fact, zero. Each term in the desired sum is ((-1)^(iw+jw+k+l+p+q))*con...

23일 전 | 0

답변 있음
PSD from Wiener Khintchine and FFT
Hi Jan-Niklas It's easier done with convolution instead of correlatation, so convolution is first here. fft does circular conv...

27일 전 | 0

답변 있음
Why the coordinate doesn't make sense after rotation matrix (rotx)?
Hi Jiali, from your results it looks like you are using the usual form of the rotation matrices, function M = Rx(theta) % an...

29일 전 | 0

| 수락됨

답변 있음
differential equation with mixed linear and log derivatives - proper setting
Hi Patrezio, d(log(x)) = dx/x, and you can insert that result in three locations to obtain eq1 = x*diff( log(y), x) + x*diff( ...

29일 전 | 1

답변 있음
Are there any built-in way to calculate inversions?
Hi Ivor, I do not know of one, but here is one way to accomplish it p = [3 6 1 4 5 2]; % for example inversions = 0; for...

30일 전 | 0

| 수락됨

답변 있음
convolution with gaussian kernel using fft
Hi LM The code below takes your approach but modifies some of the details. [1] The array sizes are odd x odd since you get th...

약 1달 전 | 1

| 수락됨

답변 있음
How could I find the maximum closed contour line?
Hello YC, Since a saddle point is where the contour lines go from closed to open, the idea is to find the location of the saddl...

약 1달 전 | 0

답변 있음
Normalization of FFT output
Hello Vittorio, In the gaussian case, the waveform has died down to zero each end (technically it's not zero, but it is smaller...

약 1달 전 | 0

답변 있음
Error in a function
Hi Morne' Here Matlab assumed that the call to the function was part of the function itself. In a script, functions must be lo...

약 1달 전 | 0

답변 있음
FFT: scaling for correct amplitude
Hi Eric, It's not the specific details of the signal so much as it is the context. If you are transforming what is basically a...

약 1달 전 | 1

답변 있음
Different eigenvectors when using eig and null functions
Hi Mohammed, I tossed in some 'double' functions to make the comparison easier A = [3 2 ; 7 -1]; syms x; a2a = sym(A); pol...

약 1달 전 | 1

| 수락됨

답변 있음
Time axis explanation required
Hi Saad, 'time' is (almost) the total length of the time record, so it will not be the spacing when setting up the time array. ...

약 1달 전 | 0

답변 있음
Analizing the charges and discharges of a capacitor conected to a square wave voltage source
Hello Virginia, As you progress along the square wave, each time you get to a new half cycle there is of course a new applied v...

약 1달 전 | 0

| 수락됨

답변 있음
How to solve a set of coupled odes that depend on derivatives
HI charlie, dx4' depends on dx2' and dx3' explicitly. But since dOmega_e_dz and dV_e_dz are also in the expression for dx4', d...

약 1달 전 | 0

답변 있음
Issue with gammainc(x,a) for small x and larger a
Hi John, Matlab does not appear to have a symbolics version of the incomplete gamma function, but it's still possible to make p...

약 1달 전 | 0

답변 있음
im using 'dsolve' for 2nd ode with dirac function but matlab returns 1/2 of constant
Hi Song-Ha Your statement " the answer should be [constant] *exp(-0.4607 * t) * sin(3.0003*t) " is missing a very important f...

약 1달 전 | 0

답변 있음
Hypergeometric Function in Matlab
Hello PM, The variable l does not come out so well in this font so I'll call it q instead. SInce both -q and -n are negative, ...

약 2달 전 | 0

| 수락됨

답변 있음
ODE45 Code Application
Hi James, [t,U] = ode45(@Velocity, [0, 20], .001); plot(t,U) function Udot = Velocity(t,U) M = 100/6*pi*0.04^3; g=9.8; A...

약 2달 전 | 1

| 수락됨

답변 있음
How to simplify a symbolic equation, but still keep the denominator
Hi LZ syms x y a b eqn1 = b*(x/a + 1) == b*y/a; % This is the equation, I would like to cancel "b" at both side, and still kee...

약 2달 전 | 1

| 수락됨

답변 있음
Eliminating and counting rows that contain a pattern that already appeared
Hello Spencer, I assume that the patterns you mean have a length of 5. The way that you have set the the problem, 44313 (B row...

약 2달 전 | 0

| 수락됨

답변 있음
Fast Fourier Transform component detection issue
Hello awezmm, This occurs because of a combination of aliasing and the spacing of the chosen frequencies. For sampling frequen...

약 2달 전 | 1

| 수락됨

Load more