# Star Strider

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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**Content Feed**

Number of line for fcontour

A somewhat different approach — syms x y z(x,y) = exp(-(x-5)^2) + cos(y) figure hfc = fcontour(z, [0 10 -2*pi 2*pi]);...

12 hours ago | 0

| accepted

ho to find index at which the 50% of the sum vector is included?

A least-squared-difference approach works — a=[3 5 7 3 5 8 9 3 1 41 6]; suma = cumsum(a); suma50 = suma(end)/2; [minv,idxv]...

14 hours ago | 1

How can I skip the first to lines from a text file and proceed to read the file with header lines in between the values?

Try this — C1 = readcell('https://www.mathworks.com/matlabcentral/answers/uploaded_files/814274/BSH_HBM_tracer_productgrid_f...

19 hours ago | 0

How to activate the low-pass filter on NI-6115?

It will likely be best to Contact Support for this. I did an online search and could find no previous posts regarding the NI-61...

23 hours ago | 0

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Function value and YDATA sizes are not equal. Can anyone help?

The problem is the randn call. With one argument, it creates an (nxn) matrix, not a vector, so of course the sizes will not mat...

23 hours ago | 1

Error with the division

Use the table2array function to convert the contents of the table to an array. Assign the arrays to new variables rather than o...

24 hours ago | 0

error [empty sym] using dsolve "Warning: unable to find symbolic solution"

It is likely not possible to derive a closed-form (analytic or symbolic) solution for those. Create an anonymous function to us...

1 day ago | 0

How to define values in a vector as NaN ?

Try this (using ismember) — A = [1 2 3; 4 5 6]; B = [2 3; 5 6]; C = ismember(A,B) A(C) = NaN .

1 day ago | 1

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Define an additional variable in ODE solver

This is all a bit confusing, since the differential equations are not them selves functions of ‘C1’ and ‘C2’, so a differential ...

1 day ago | 0

Can't Uninstall, What Should I Do?

Option #1: Contact Support The uninstall function deletes registry entries as well, however a fresh install should over-write...

1 day ago | 0

symbolic variables into double array, observability matrix

The variable values need to be provided in order to use the Control System Toolbox funcitons. To do this symbolically, create...

1 day ago | 0

How can I estimate the parameter of reaction kinetics using ODE solver?

I am not absolutely certain how to approach this because chemical engineering is not an area of my expertise. First, I would ...

2 days ago | 0

Question in continuous time signals

Everything in a computer are discrete, not continuous (except the voltages on the chips themselves and the outputs of a soundcar...

2 days ago | 0

How to solve the implicit equation

First, a multiplication operator (my best guess, anyway) is missing: ((alfa*Vt*Vmpp*(2*Impp-Isc))/((Vmpp*Isc+Voc*(Impp-Isc))*(...

2 days ago | 0

How can we combine the two figures?

‘When you execute the code below, two plots are drawn.’ No, not without knowing what the variables are. However the prob...

2 days ago | 0

Calculate this matrix in a more general and shorter way

Yes, actually. However since it appears that the objective is to do a Fourier transform, I would set it up a bit differently ...

2 days ago | 0

ODE45/ODE15 inquiry about nonlinear spring

Since the system appears to describe a differential-algebraic equation, see the documentation section on Solve Differential Alge...

2 days ago | 0

Symbiological output using 'syms' and 'pretty' commands

Experiment with the indexing into the expressions (since this is a straightforward solution to a number of otherwise difficult p...

2 days ago | 0

How do I reflex a plot?

Try this — u = -8:1:1.3; v = -pi:pi/10:pi; for k = 1:numel(v) x{k,1} = 1 + u + exp(u)*cos(v(k)); y{k,1} = v(k) +...

3 days ago | 0

how to increase function values through its derivetive

Do some simple experiments to see what produces the desired result — syms k x dx1 = 2*x; ...

3 days ago | 0

Problem to solve integration

Change this — f = @x sin(x); to this — f = @(x) sin(x); That should work. .

3 days ago | 0

Removing a particular legend from plot

The first two lines have the same line style. To see them individually, choose a different line style for each. To label t...

3 days ago | 0

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how to solve the following equation?

Try this — a=[1,2,3]; afcn = @(b) ((b-2).*(b+1))./((b+3).*(b-1)); [estb,fval] = fminsearch(@(b) norm(afcn(b) - a), rand) ...

3 days ago | 0

| accepted

How to plot 3D filled contour ?

It would help to know the data and the desired result. One option is to use the surf function and contour3 — [X,Y,Z] = peak...

3 days ago | 0

Using ode45 for a non linear differential equation with a term in a vector form

I do not understand the problem. Is the objective to estimate a parameters of the differential equation from data? The tim...

3 days ago | 0

| accepted

why do I get an error "First input argument must be a function handle"

I have no idea what the code does. See if this paproximates the desired result — nUn = 2000; nU2n = 1500; nU3n = 200;...

4 days ago | 1

I need help solving RC circuit using Leplace inverse, then graph the output which is in the symsum form

Sometimes a bit fo force (such as using vpa) is necessary — syms s t Ys2(s)=((2*s^2+7*s+3)/(2*s^3+11*s^2+15*s+4)*(2*s+2)/(...

4 days ago | 1

| accepted

2D contour plot with given matrix

Two possibilities — M = [25, 25, 25 111.5, 137.8, 245.1 146.3, 178.3, 296.4 111.5, 137.8, 245.1 25, 25, 25]; figure ...

4 days ago | 0

| accepted

from curve fit to look up table

The question is a bit ambiguous. Interpolation of some sort would appear to be the best option, and of course the approach de...

4 days ago | 0

Curve fitting for multivariable

There are several options. I’m using fminsearch here. xdata = ... [0.882263937 0.882263937 0.882263937 0.882263937 0...

4 days ago | 0

| accepted