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Alan Stevens


Last seen: 3 days ago Active since 2020

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Answered
ode45 not able to solve one particular IVP
How about: y = -3:0.4:3; % pick values of y x = -3:0.4:3; % pick values of x [xg,yg] ...

6 days ago | 0

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Answered
Erro ao usar matlab.internal.math.interp1 Os pontos de amostra devem ser exclusivos.
Well, this gets it working, but you need to check your function equilibrio as it doesn't cross zero until T is between 3400 and ...

2 months ago | 0

Answered
Generate a vector with elements based on certain elements in another vector
Like this? A = [0;0;0;0;0;1;1;1;1;1]; B =zeros(size(A)); ptr = find(A==1); B(ptr(1):ptr(1)+2)=1

2 months ago | 1

Answered
Solving the problem for the free extremum of a function of several variables - numerical determination local minimum.
Here's a "starter for ten" with the Newton-Raphson method: % Newton-Raphson Approach % Function f = @(x,y)x^4+5*x^2-9*x^2*...

2 months ago | 0

Answered
Finding max value of 1D vector when all values could be negative
Try [M, I] = max(abs(DD)) M = DD(I)

2 months ago | 0

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Answered
Issue with correct Fanno parameter when using flowfanno function.
fL/D suggests the Darcy-Weisbach friction factor is being used. 4fL/D suggests the Fanning friction factor is being used. (T...

3 months ago | 0

Answered
Using Runge Kutta to solve second-order differential equations with two degrees of freedom
Like this? omega = 0.05:0.05:20; tspan = [0 2*pi]; xmax = zeros(1,numel(omega)); for i = 1:numel(omega) X0 = [0...

3 months ago | 0

Answered
Changing the value of only one parameter causes a problem (possibly with while loop)
You can see from the following that when i = 3, 4 and 7, V(i) stays at a constant value greater than Vmax %% Constants and Assu...

3 months ago | 0

Answered
Why is the set of numbers p2 not showing up on my graph
Should it be more like this? (Though I don't recognize the value you have for the gas constant; and temperature would normally b...

3 months ago | 0

Answered
Reproducing Water Defect Mode Plot in MATLAB (Only Getting 0.1748 Transmittance Instead of Sharp Peak of 1)
The size of the peak is very sensitive to the increments in your lambda range: n_Si = 3.465; % Refractive index of Si n_SiO...

3 months ago | 1

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Answered
I'm trying to solve jeffry hamel equation using RK4 but it's not giving output as expected.
The following code produces something very close to the plot that you want to see. However, the values of g(1) are nowhere near...

4 months ago | 1

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Answered
i try to put two plot in one graph using legend but one of them just looks been 'cut off', can someone help me to fix this problem
Plot both curves the same way (i.e. t then x)! x0=2.1; g=9.81; k=45; m=7; t=0:0.1:6; x1=@(t) x0*cosd(t*(sqrt(k/m))); x_t_...

4 months ago | 0

Answered
Implementation of the analytical expression for the magnetic field of a circular current loop and interpretation/representation of the results
When I run it I get different signs as well as slightly different magnitudes: %% Analytical calculation of the magnetic field o...

5 months ago | 0

Answered
How to remove gaps in timeseries plot to have a continuous graph
Include a NaN in the data list between each data set.

5 months ago | 0

Answered
what the reason behind roundoff error inside while loop
Compare the following dt = 0.1*16^-1; t = 0; while t<1 t = t+dt; end disp(t) t = 0; c = 1; while t<1 t = c...

5 months ago | 0

Answered
Something doesn't work for me in fit
Here's a fit using fminsearch (I just used a quick but coarse approach- the code can be made much cleaner!). v=[10 30 5...

5 months ago | 0

Answered
Plotting while skipping the middle point in a vector
Something like this? tic v1 = [1 2 3 4 5 8 9 10 20 21 22 30 31 32]; dv = diff(v1); ix = find(abs(dv)>1); v = []; s2 = 0; f...

6 months ago | 1

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Answered
help with nested loop and plot
Here's another way, still using nested loops: n= 101; x = linspace(-100, 100, n); y = linspace(-100, 100, n); [X, Y] = meshg...

6 months ago | 0

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Answered
How to integrate an implicit acceleration function to a fitting pair of graphs of velocity and displacement
Look up ode45 for the integration (for a fixed set of parameters) and fminsearch for fitting the parameters to known data.

6 months ago | 0

Answered
Brush: How can I change the font color of the displayed X and Y range?
Select the Property Inspector, select the text, choose a color. (The following code is just to get the image uploaded) I=imrea...

7 months ago | 0

Answered
how to use an integral function inside a for loop? i need to find the value of function that chages as i chages .then using this values i need to find another integral.
Are you looking for something like this? r0 =0.1; u =[1:7]'; Q =zeros(length(u),1); E =zeros(length(Q),1); Q = @(x)0.023*(r...

7 months ago | 0

Answered
Simpson integral - problem with writing the formula
Should be x(i) etc. not a(i). Also be careful with brackets. % Test 1 a = 0; b = 1; n = 10; f = @(x)1-x+x.^3; I = simpson(f...

7 months ago | 0

Answered
How do I apply iteration method to an integral?
Look up help on function fzero.

8 months ago | 1

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Answered
How can I plot a reflection angle of a projectile in a kinematics model? Overlay projectile motion plots?
Surely you only need to reverse the x-velocity? imperialBallVelocity = 52.20; release_angle = 42; release_height = 64.2; %Ki...

8 months ago | 1

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Answered
Why am I receiving this error?
You have 4 layers layer_angles = [45, -45, -45, 45]; but data for only three mid_plane_strains = [0.05, 0.00, 0.00]; % Mid-p...

8 months ago | 0

Answered
Function g Returns Only 2 Values Instead of Array - Vectorized Operation Issue in MATLAB
You have g as a function of x2, but x2 doesn't appear on the right-hand side!

8 months ago | 0

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Answered
Solve for x with given equation
Look up the help on function fzero. And don't forget that Matlab doesn't recognise implicit multiplication. x(...) should...

8 months ago | 0

Answered
power method with rayleigh coeff
Make sure you call the function with the arguments in the same order as those defined in the function! A=[4 1 -1 0;1 3 -1 0;-1 ...

8 months ago | 0

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Answered
Fill area between two vertical curves
Like this: value = [186.7646 198.4115 191.1406 180.8430 175.7136 ... 167.7459 151.2865 144.5964 139.8148 139.4305 188.2865 204...

9 months ago | 2

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Answered
Simplificar el resultado como valor numerico
Why not simply: p1=[2;3] ; x0_1=@(theta) [cos(theta); sin(theta)]; % =[x1*x0; x1*y0] y0_1=@(theta)[-sin(theta); cos(theta)];...

9 months ago | 1

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