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Star Strider


Last seen: Today Active 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

NOTE: I do not respond to emails or personal messages, unless they are about my File Exchange contributions.

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Answered
Error finding Linear Regression with polyfit and \
There is a NaN value in the temperature data. Try this: LD = load('data.mat'); data = LD.data; x = data.LOCAL_DATE; xd...

3 hours ago | 0

Answered
How to find tangent line of curve
See: How to draw a tangent line on a curve .

10 hours ago | 0

Answered
plot 2D matrix data
The pcolor function requires a matrix argument, and the data provided here are a (5000 x 3) matrix with ‘X’, ‘Y’ and ‘Z’ columns...

10 hours ago | 0

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Answered
How can I differentiate an abstract symbolic function?
I am not certrain that I understand what you want to do. See if the diff documentation section on Differentiation With Respec...

10 hours ago | 0

Answered
Trying to get time between each start and stop & total time per day from a text file.
Tha blank values in the ‘Elapsed_Time’ column will not work with duration arrays, so those end up being zeros instead. I create...

21 hours ago | 0

Answered
I want to find the value of two constants from an equation with two variables
@NDC — To estimate the initial parameters for this, since is known, the asymptote as will be , and that gives a way to estim...

1 day ago | 0

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Answered
Why do I receive "Error using lsqcurvefit (line 251) Function value and YDATA sizes are not equal."
Do element-wise division F2 = @(x,xdata)(x(1)*sin(xdata*pi/180)*(1-exp(-50*x(2)))./(1-cos(xdata*pi/180)*exp(-50*x(2)))); ...

1 day ago | 0

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Answered
Cells detect and Cells numers in array
M1 = readmatrix('https://www.mathworks.com/matlabcentral/answers/uploaded_files/701747/1.xlsx') time_desired = [0, 10, 60, ...

1 day ago | 0

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Answered
How can I compare a 1000 Hz signal with a 1024 Hz signal?
It is not obvious to me how you want to compare them. One option is to take the fft of both signals and then compare those re...

1 day ago | 0

Answered
Aligning 2 Signals as a function of third signal
I am not certain what you want to do. See if the alignsignals function will do what you want. Another option may be findsign...

2 days ago | 0

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Answered
Making a 2d scatter plot with multiple data sets and color map
Use the third argument of scatter to determine the size of the points, and the fourth argument of scatter to determine the colou...

2 days ago | 0

Answered
How do I plot my differential equation on Matlab?
Of copurse it’s going to be a straight line! After evaluating the functions, look at ‘(tval,Vp)’ and ‘(tval2,V)’. They are al...

2 days ago | 0

Answered
How to Overlay Curve Fit Over Bar Plot Without Overriding Data?
Include the independent variable ‘Year’ in the bar call, and change the xlim values: Year = 2013:2019; Video_Cost = [11.09, ...

3 days ago | 1

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Answered
How to plot specific range of values in a plot?
Perhaps: plot(X([2:5 7:end]),Y([2:5 7:end]),'ko') Create vectors with specific values by enclosing them in square brackets []...

4 days ago | 0

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Answered
Please assist! Z1= exact solution; Z2= approximate solution. Now i want to plot a 2D graph of the exact and approximate solution in ONE graph to campare the results
Try this: alpha=1; t=0.004; [x,t] = meshgrid(-4:.1:4, 0.1:.2:0.4); exact=(sech(x/4-t/4)).^2; f0=(sech(x/4)).^2; f1=(s...

4 days ago | 0

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Answered
Ode 45 / Ode xx: Solve time depending system of equations (2nd order)
The clear and clc calls are not necessary, global variables are never advisable, and the syms call is also not necessary. Creat...

4 days ago | 1

Answered
Reorganization of experimental data
The data file you attached does not appear to bear a strong resemblance to the data file you quoted. I chose to use textscan ...

5 days ago | 0

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Answered
Finding the intersection points between two curves
Several options — h=20; K=13.6; l=1148e-6; f1 = @(beta)tan(beta*l); f2 = @(beta)2*h*beta*K./(K^2*beta.^2-h^2); figure ...

5 days ago | 0

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Answered
How to obtain model parameters by fitting experimental data to the monod model. monod model.
It should be relatively straightforward to adapt your system to existing code. One example is Parameter Estimation for a Sys...

5 days ago | 0

Answered
How can i calculate PDF and CDF of non-parametric distribution?
I am not certain what your data are. If ,they are appropriate for the function, I would begin with the ecdf function, since it ...

5 days ago | 1

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Answered
Issue solving a non-linear differential equation in Matlab
‘Am I wrong?’ No. The result is not always as simple as it might be. In R2021a, the Symbolic Math Toolbox apparently simp...

6 days ago | 0

Answered
isosurface with wall thickness
There does not appear to be any way to change the thickness of the plotted surface. The best I can come up with is the revise...

6 days ago | 0

Answered
How can I plot integral of this equation?
Try something like this — % clc; figure('color','white'); while(1) sigma.phi=input('Enter 0.1 in a.u.: '); mu=input('Enter...

6 days ago | 0

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Answered
How to find and chart the frequency of a letter in column with histogram.
Perhaps — Col = {'HFHFHSHHAJHJA'; 'HSAJHFGFSAGJ'; 'HSGHSFFJHJ'}; T = cell2table(Col) RowSum = cellfun(@(x)sum(x=='H',2),T{:,...

7 days ago | 0

Answered
Error with find(X) statement
Taking a wild guess, since the test is: states=find(sum(UNITARY_MATRIX)~=1.0) it is likely encountering floating-point approx...

7 days ago | 0

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Answered
vector gives 0 integral
There quite definitely is! In your call to it: sd = trapz((z),0,20) the function interprets ‘z’ (the parentheses aren’t n...

7 days ago | 0

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Answered
How to shade/color overlapped area in the graph?
I honestly have no desire to download ‘plotxx’ and learn its intricacies, so I used yyaxis instead here. The same approach sh...

7 days ago | 2

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Answered
Create line between plot points
Yes. x = [0 10 20 30]; y = [355 433 510 590]; figure plot(x, y, '*-r') grid Ax = gca; Ax.XMinorGrid = 'on'; Ax.YMino...

7 days ago | 0

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Answered
plotting a phase plane with a system of linear diff equations.
Using the numeric ODE solvers, likely the easiest way to do that is to use odeset to set options, and then choose 'OutputFcn', @...

8 days ago | 0

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Answered
Why am I getting a Parse error for a sequence?
It’s missing an equal (=) sign: for it = 1:MaxIt %this starts 'for' loop and runs for MaxIt times. .

8 days ago | 1

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