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Star Strider


Last seen: Today
15.873 total contributions since 2012

Hic sunt dracones!

PROFESSIONAL: Physician (M.D.): Diplomate of the American Board of Internal Medicine; M.Sc. Biomedical Engineering: Instrumentation, Signal Processing, Control, System Identification, Parameter Estimation

NON-PROFESSIONAL: Amateur Extra Class Amateur Radio Operator; Private Pilot, Airplane Single Engine Land, Instrument Rating Airplane; Gamer

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Answered
How to solve Coupled Differential Equations
Try this — syms x(t) y(t) x0 y0 Dx = diff(x); Dy = diff(y); ode1 = Dy-Dx == 2 - x ode2 = 2-Dy - Dy == 3 + 2*y S = dsolve...

ongeveer een uur ago | 0

Answered
How to interpolate a matrix ?
Try this — M=[ 3.2 5 4.1 4 5.6 3 6.7 ...

ongeveer een uur ago | 0

| accepted

Answered
Vector counting syntax help?
Try this — A = [1 1 1 1 2 3 3 5 5 5 5 6 6 7]; [Au,~,ix] = unique(A,'stable'); Count = accumarray(ix,1); Result = table(Au(:...

ongeveer 6 uur ago | 0

| accepted

Answered
How to get multiple variables in 'assume' ?
Declare them in the syms call as positive. MATLAB defines positive as values greater than 0. See the documentation section o...

ongeveer 7 uur ago | 0

| accepted

Answered
signal does not show filtered, using filter()
Use freqz to see what the filters are actually doing — Fs1 = 500; %Sampling Frequency ync = [.25, .5, .25]; ync1 = [-.085 ....

ongeveer 19 uur ago | 0

Answered
Trying to fit parameters for an ODE model to real data using lsqcurvefit
‘... I can't seem to find any real differences between the code I've constructed and that example.’ I agree that the initial ...

1 dag ago | 0

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Answered
how take a mathematical function from user
I would use the inputdlg function — prompt = {'Enter f(x,y):', 'Enter g(x):'}; response = inputdlg(prompt) f = str2func(['@(...

1 dag ago | 0

Answered
Characteristics of a step response plot
Try something like this (using a transfer function from the documentation) — sys = tf([1 5 5],[1 1.65 5 6.5 2]); stinf = step...

1 dag ago | 0

Answered
I want to separate the signal from the noise with the help of a low pass filter.
I could not figure out which of those signals you want to filter, so I arbitrarily chose ‘t1’ and ‘y1’. They are not consiste...

1 dag ago | 0

Answered
How to change X axis in the form of percentage
Try something like this — x = linspace(77, 146); y = -60 - 15*sin(2*pi*x/50); figure plot(x, y) Ax = gca; xt = Ax.XTick...

1 dag ago | 1

Answered
Plotting a filter as a function of cyclic frequency using freqz()
Your approach is correct. The reason the freqz plot did not look correct is that you were passing the filtered signal to it, no...

1 dag ago | 0

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Answered
Coupled second order differential equation
Start by writing the equations using the Symbolic Math Toolbox. Specifically, see the documentation on the dsolve function. ...

2 dagen ago | 0

Answered
ode45 not working
There are a few errors, all easily solved. Try this — m = 5; g = 9.81; r = 0.470; I = 0.37; ks = 0.012; dt = 0.01; ...

2 dagen ago | 0

Answered
How to tell matlab that y is a function of x; not a constant
In the initial syms call, declare ‘y(x)’ instead of ‘y’ — syms x y(x) z z=x*y; Dz = diff(z,x) ...

2 dagen ago | 1

| accepted

Answered
Locating rising peaks of variable amplitude pulses
I am not certain what you are doing, or what the ‘overlaid pulses situation’ means. There appears to be a significant amount ...

2 dagen ago | 0

Answered
How do I make a low-pass filter on this data set?
For an EKG, use the bandpass function with the lower cutoff at 1.5 Hz and the upper cutoff between 45 Hz (if there is mains or p...

3 dagen ago | 0

Answered
Adding text to each subplots
Use xlim and ylim to make the text positions relative to the axes — x1 = linspace(0,10, 25); y1 = exp(-0.1*x1); x2 = linspac...

3 dagen ago | 0

| accepted

Answered
Error in App Designer " Undefined function 'sym2poly' for input arguments of type 'char'.."
Apart from the app code, apparently the numerator and denominator polynomials are not being transofmred into symbolic variables....

3 dagen ago | 1

| accepted

Answered
How to get tfest() to focus on a frequency range (or is something else wrong)?
Without any data or code, and since I have no idea how that was plotted, the only solution I can offer is to use the compare fun...

3 dagen ago | 0

Answered
CIplot unable to fill on log-x axis
I am not certain what you are doing. However in many situations, it is easier to initially plot in a linear scale, then afterwa...

3 dagen ago | 0

| accepted

Answered
Numerical integration using Trapz
That should produce one scalar value as ‘F’, so the subscripts are not necessary. I would do something like this — F = trap...

3 dagen ago | 0

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Answered
Data is not importing? SOS
It is not importing because the correct approach to reading .wav files is to use audioread. Try that. It should do what you ...

3 dagen ago | 0

Answered
unable to solve with respect to y
Try this — syms s x y(x) y0 Dy0 C1 C2 Dy = diff(y); D2y = diff(Dy); ode=(x^2*D2y)-(3*x*Dy)+(3*y)==(2*x^4*(exp(x))) y(x,C1,...

4 dagen ago | 0

Answered
What would be a best interpolation method to get test data for a specific temperature?
I would just use interp1 — TestData = sortrows(randi([0 200], 15, 4),1) InterpTemps = [0 40 100]; Interp_234 = interp1(TestD...

4 dagen ago | 0

Answered
xlsread isn't storing all the cell values from a column
Try something like this — T1 = readtable('YourExcelFile.xlsx', 'Range','A1:E19') That will import everything as a table, and ...

4 dagen ago | 0

| accepted

Answered
Output argument "K" (and maybe others) not assigned during call to "linear_kernel".
Why not just — K = dot(x1,x2) instead? See the documentation on the dot function for details.

4 dagen ago | 0

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Answered
The value of equation
I have absolutely no clue as to what you want. Try this — syms x u x3 %x = (0:1:4) L1 = 8; L =...

4 dagen ago | 0

Answered
Calculating the Standard Deviation
Two options are to either calculate it directly, or use the normalize funciton — y = readmatrix('https://www.mathworks.com/mat...

4 dagen ago | 0

Answered
How to Numerically Integrate Vector with Timestep
Use the trapz function (or cumtrapz, dependng on the result you want), The vector with respect to the numeric integration (time...

4 dagen ago | 1

Answered
Getting the area of a surface integral from Matlab
See if simplifying it does what you want — syms phi the x = cos(phi).*sin(the); y = sin(phi).*sin(the); z = cos(the); dens...

4 dagen ago | 1

| accepted

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