Answered

Draw shapes not in a graph

Try something like this: x1 = rand(1,5); y1 = rand(1,5); x2 = rand(1,7); y2 = rand(1,7); figure plot(x1, y1, 'or', 'Mar...

Draw shapes not in a graph

Try something like this: x1 = rand(1,5); y1 = rand(1,5); x2 = rand(1,7); y2 = rand(1,7); figure plot(x1, y1, 'or', 'Mar...

5 dagar ago | 0

Answered

please help me (dsolve)

The single quotation marks are likely the problem. Try this slightly edited version: syms y(t) Dy = diff(y); D2y = diff(...

please help me (dsolve)

The single quotation marks are likely the problem. Try this slightly edited version: syms y(t) Dy = diff(y); D2y = diff(...

5 dagar ago | 0

Answered

How Do I Fitting a 3 Unknown Parameter Model?

There are several functions available to estimate the parameters. This uses fminsearch because everyone has it: VFTfcn = @(b,...

How Do I Fitting a 3 Unknown Parameter Model?

There are several functions available to estimate the parameters. This uses fminsearch because everyone has it: VFTfcn = @(b,...

6 dagar ago | 0

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Answered

Matlab interpolation between two surfaces

Experiment with this: x = linspace(-5, 5, 20); y = x; [X,Y] = ndgrid(x,y); z = @(x,y,s,h,a) a .* exp(s*(x.^2+y.^2)) + h; ...

Matlab interpolation between two surfaces

Experiment with this: x = linspace(-5, 5, 20); y = x; [X,Y] = ndgrid(x,y); z = @(x,y,s,h,a) a .* exp(s*(x.^2+y.^2)) + h; ...

6 dagar ago | 0

Answered

complementary error function (surf plot)

Add: [X,T] = ndgrid(x,t); and it works: x = linspace(0,10^(-6),20); t = linspace(0,5,5); [X,T] = ndgrid(x,t); u0 = 10^(-...

complementary error function (surf plot)

Add: [X,T] = ndgrid(x,t); and it works: x = linspace(0,10^(-6),20); t = linspace(0,5,5); [X,T] = ndgrid(x,t); u0 = 10^(-...

6 dagar ago | 0

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Answered

Solving equations using Laplace transform

Unless you are solving a partial differential equation, such that the Laplace transform produces an ordinary differential equati...

Solving equations using Laplace transform

Unless you are solving a partial differential equation, such that the Laplace transform produces an ordinary differential equati...

7 dagar ago | 0

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Answered

Answers editor seems to be broken

The website was updated. I had the same problem, and it turned out that Rena’s suggestion that clearing the Firefox cache solve...

Answers editor seems to be broken

The website was updated. I had the same problem, and it turned out that Rena’s suggestion that clearing the Firefox cache solve...

7 dagar ago | 0

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Answered

Error using atan2 Inputs must be real.

If you want to compute the phase angle of a complex number, use the angle function.

Error using atan2 Inputs must be real.

If you want to compute the phase angle of a complex number, use the angle function.

7 dagar ago | 0

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Answered

How to get unknown number of variables to be all same length through interpolation

Try this approach: V1 = sort(rand(1,5)); % Original Vector V2 = sort(rand(1,10)...

How to get unknown number of variables to be all same length through interpolation

Try this approach: V1 = sort(rand(1,5)); % Original Vector V2 = sort(rand(1,10)...

7 dagar ago | 0

Answered

ode15s error（Genetic algorithm for differential equation parameter identification）

I cannot follow your code. See Ode system solution with unknown constant for one example of an approach that generally works....

ode15s error（Genetic algorithm for differential equation parameter identification）

I cannot follow your code. See Ode system solution with unknown constant for one example of an approach that generally works....

7 dagar ago | 0

Answered

ODE with time-varying coefficients

The Answers Comment and Answer windows are malfunctioning. I am having serious problems with the lack of formatting and other o...

ODE with time-varying coefficients

The Answers Comment and Answer windows are malfunctioning. I am having serious problems with the lack of formatting and other o...

7 dagar ago | 0

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Answered

designing a chebyshev type 2 high pass filter

Start with the cheb2ord function to define all the variables appropriately.

designing a chebyshev type 2 high pass filter

Start with the cheb2ord function to define all the variables appropriately.

8 dagar ago | 0

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Answered

Differential eq of a hot storage tank

The time intervals the ODE solvers use are whatever you define them to be, since they have no inherent unit. In the ‘m’ assignm...

Differential eq of a hot storage tank

The time intervals the ODE solvers use are whatever you define them to be, since they have no inherent unit. In the ‘m’ assignm...

8 dagar ago | 0

Answered

Output numeric array from symbolic evaluation

After the loops: T = vpa(T) creates the entire array as decimal fractions.

Output numeric array from symbolic evaluation

After the loops: T = vpa(T) creates the entire array as decimal fractions.

8 dagar ago | 0

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Answered

How can I draw the fitted curve and find the initial slope of the attached plot?

Try this: D = readmatrix('Example.xlsx'); x = D(:,1); y = D(:,2); p = polyfit(x, y, 3); yfit = polyval(p, x); dp = poly...

How can I draw the fitted curve and find the initial slope of the attached plot?

Try this: D = readmatrix('Example.xlsx'); x = D(:,1); y = D(:,2); p = polyfit(x, y, 3); yfit = polyval(p, x); dp = poly...

8 dagar ago | 0

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Answered

Mathematical Modelling for parametric analysis

See the documentation for regress to understand how to work with the ‘carsmall.mat’ file. You should have it, since it’s been...

Mathematical Modelling for parametric analysis

See the documentation for regress to understand how to work with the ‘carsmall.mat’ file. You should have it, since it’s been...

8 dagar ago | 0

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Answered

Invalid indexing for dsolve

The equations are nonlinear, and for most nonlinear differential equations, an analytic solution does not exist. Try this ins...

Invalid indexing for dsolve

The equations are nonlinear, and for most nonlinear differential equations, an analytic solution does not exist. Try this ins...

9 dagar ago | 0

Answered

How to extract numbers from .dat file

One option: fidi = fopen('Nasis Vangelis.dat','rt'); k = 1; while ~feof(fidi) readline = fgetl(fidi); C{k} = regex...

How to extract numbers from .dat file

One option: fidi = fopen('Nasis Vangelis.dat','rt'); k = 1; while ~feof(fidi) readline = fgetl(fidi); C{k} = regex...

9 dagar ago | 0

Answered

How to Plot a Continues Tiime Signal

I have no idea what ‘x(t)’ is. I usually code the uint step function as: u = @(t) t>=1; althoug other options are possible...

How to Plot a Continues Tiime Signal

I have no idea what ‘x(t)’ is. I usually code the uint step function as: u = @(t) t>=1; althoug other options are possible...

9 dagar ago | 0

Answered

read data from delimited text file

This is one of the more difficult files I have managed to import! See if this does what you want: fidi = fopen('water.txt')...

read data from delimited text file

This is one of the more difficult files I have managed to import! See if this does what you want: fidi = fopen('water.txt')...

9 dagar ago | 0

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Answered

A simple LowPass Filter

Using a window inplies a FIR filter. Start with the fir1 function to design it, and freqz to analyse it. Filter your signal wi...

A simple LowPass Filter

Using a window inplies a FIR filter. Start with the fir1 function to design it, and freqz to analyse it. Filter your signal wi...

10 dagar ago | 0

Answered

Printing my Integration step by step

Use cumtrapz instead of trapz: L=F./W; lambda= 2*cumtrapz(W,L) figure plot(W, lambda) grid xlabel('W') ylabel('\int\la...

Printing my Integration step by step

Use cumtrapz instead of trapz: L=F./W; lambda= 2*cumtrapz(W,L) figure plot(W, lambda) grid xlabel('W') ylabel('\int\la...

11 dagar ago | 0

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Answered

Cell-Matrix, I can't extract values

Change the code slightly to: F = openfig('phi_1.fig'); ax = gca; lines = findobj(ax, 'Type','Line'); for k = 1:numel(lines)...

Cell-Matrix, I can't extract values

Change the code slightly to: F = openfig('phi_1.fig'); ax = gca; lines = findobj(ax, 'Type','Line'); for k = 1:numel(lines)...

11 dagar ago | 0

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Answered

Mesh with griddata, how eliminate undesidered extra surface

Without your data, posting an exact solution (if one even exists) is not possible. One possibility is that your data are actu...

Mesh with griddata, how eliminate undesidered extra surface

Without your data, posting an exact solution (if one even exists) is not possible. One possibility is that your data are actu...

11 dagar ago | 1

Answered

why surface plot is connecting its edges?

Try this for the file provided, and the others that likely have similar formats. Note — It is only necessary to reshape the ...

why surface plot is connecting its edges?

Try this for the file provided, and the others that likely have similar formats. Note — It is only necessary to reshape the ...

11 dagar ago | 0

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Answered

Help finding R^2 value for curves

I appreciate your quoting my code! The value is not difficult to calculate. One example using a much simpler single-var...

Help finding R^2 value for curves

I appreciate your quoting my code! The value is not difficult to calculate. One example using a much simpler single-var...

11 dagar ago | 0

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Answered

Predicting the kinetic constant of a reaction based on experimental data

If you have the Global Optimization Toolbox, the code I attached will estimate the parameters with reasonable accuracy, although...

Predicting the kinetic constant of a reaction based on experimental data

If you have the Global Optimization Toolbox, the code I attached will estimate the parameters with reasonable accuracy, although...

12 dagar ago | 0

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Answered

Trouble with my function

You need to tell your ‘derivative’ function what ‘y’ is. Changing ‘derivative’ to an anonymous function (for my convenience) ...

Trouble with my function

You need to tell your ‘derivative’ function what ‘y’ is. Changing ‘derivative’ to an anonymous function (for my convenience) ...

12 dagar ago | 0

Answered

Error using plot3 - Vectors must be the same length

See if this does what you want: theta = [0:0.101:pi/2,3*pi/2:0.01:2*pi]; rho = sqrt(cos(theta)); [x,y]=pol2cart(theta,rho); ...

Error using plot3 - Vectors must be the same length

See if this does what you want: theta = [0:0.101:pi/2,3*pi/2:0.01:2*pi]; rho = sqrt(cos(theta)); [x,y]=pol2cart(theta,rho); ...

12 dagar ago | 0

| accepted