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Alan Stevens


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401 total contributions since 2020

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Answered
How can I plot this second-order differential equation
More like this perhaps omega = 0.8:0.1:1.5; n = numel(omega); for i = 1:n dydt = @(t,y) [y(2); -0.2*y(2) + y(1) - y(1)...

1 hour ago | 0

Answered
How can I use a string in legend()?
You could use Legend = ['HS+HG = 0.5+5' ;'HS+HG = 1+5']; legend(Legend) But make sure there are the same number of characte...

19 hours ago | 0

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Inverse hyperbolic fit to data
Here's an alternative, with V as the independent variable and P as the dependent one: % Data P = [5 7.5 10 12.5 15 17.5 20 25...

22 hours ago | 1

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make a function recursive (koch snowflake)
The following replaces the "for iteration = 1:n" loop with a recursive function %Koch draws Koch snowflake %n is how many iter...

1 day ago | 0

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What is wrong with my code?
Your code works if you put in sensible numbers for step size and velocity. Zero is not sensible!

1 day ago | 0

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How can I solve it: Matrix dimensions must agree.
Replace if M ==[] with if isempty(M)

2 days ago | 0

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Getting a wrong answer using solve()
Running your code as is (I copied and pasted, with no changes), I get >> syms pa p1a; c=1.056; Eq1= -8 * p1a ^ 2 + (12 * c -...

2 days ago | 1

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Best fit line on Semi log graph
Like so data=[0.891 35784.525582 0.91 39142.72 0.815 17679.26 0.891 25582 0.8861 30168.052]; ...

2 days ago | 1

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Answered
How to Plot a Fourier Series?
Here's the cosine version. You can add the sin version and play with different ranges for n: x = -24:0.1:24; n = 10; ycos = f...

3 days ago | 0

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Answered
How to plot an implicit and dicontinues function?
Do you mean like this (type doc contour for more detail): x1 = -2:0.01:2; x2 = -2:0.01:2; [x, y] = meshgrid(x1, x2); z = T...

3 days ago | 0

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Answered
Multiple roots formula with Matlab
I think your formula shoud be First define your function and its first two derivatives in Matlab f = @(x) x.^4- 6*x.^3 + 12*...

3 days ago | 0

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Answered
How to plot an implicit and dicontinues function?
Something like the following? (You could use surfc if you want contours as well): x1 = -10:10; x2 = -10:10; [x, y] = meshgr...

3 days ago | 0

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plotting the graph, help me~~
You had a few mismatches between vgs and Vgs. Matlab is case sensitive. Try W=40; Vth=0.45; Leff=0.15; k=4.255*(10^-4)*(W/L...

3 days ago | 0

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Answered
Recursive Function in Matlab (Help)
The Newton_Raphson is a recurrence formula, not a recursive one, so what you have written is correct. Look at the last value o...

3 days ago | 0

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NUMERICAL INTEGRATION USING SIMPSONS
The problem is that you have many values of lambda. To deal with this use a loop to do the integration for each value of lambda...

3 days ago | 0

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Answered
non linear implicit equation
Surprisingly, this has an explicit solution for y (I didn't use Matlab to get it as I don't have the symbolic toolbox to hand) ....

4 days ago | 1

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Answered
How to write the codes for this gamma function?
Compare your coded value of 154056.7 with the equation's value of 154.056.

4 days ago | 0

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Poisson Boltzmann eq. with an infinite boundary condition
I suspect the initial gradient required to get zero at infinity is an irrational number (or possibly a rational number with a la...

4 days ago | 0

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Answered
How to solve s system of coupled nonlinear ODES already given the state vector
You need to solve for all xdots simultaneously - this is done in matrix format below. There were also a number of errors in you...

4 days ago | 1

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Answered
How to round UP to 1 decimal value?
ceil(x*10)/10

4 days ago | 0

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Answered
Generate and Plot N Points Picking Random Points on Triangle
More like the following; rng('shuffle'); n = 1000; % Set number of points as desired % Let (0,0) be vertex 1, (0,2) be verte...

5 days ago | 0

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Answered
Finding the streamlines of a complex potential for a Joukowsky transform from a unit circle to a flat plate.
x=0:. There was a strange vertical line that O thought was related to this. However, you could put it back and see if it makes a...

5 days ago | 1

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Finding the streamlines of a complex potential for a Joukowsky transform from a unit circle to a flat plate.
There are some typos in the paper by Smith et al, and some steps left out. I think the following generates figure 18: x = [-2:...

5 days ago | 1

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Answered
How to do write the codes for this summation problem?
Having defined n and T then B = 1./(log(T) - mean(log(T))); Note that in Matlab, log is log to base e.

5 days ago | 0

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how to graph this system of questions into mathlab
You can define the function as follows f = @(v) (-0.001778*v.^2+0.05333*v).*(v<30); The (v<30) part simply multiplies the rest...

5 days ago | 0

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Initialize values at time = 0
You probably want to replace if (lambda(:,1) == lambda(1,1)) & (lambda(:,2) == lambda(1,2)) by if (lambda(r,1) == lambda(1,1)...

5 days ago | 0

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Answered
ode arguments error in function
For the last line in your function you need dYfuncvecdW = [dXdW; dydW]; Notice the semicolon after dXdW Also your plot comman...

6 days ago | 0

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How do I solve Time dependent parameter in ODE
Perhaps your code needs to be structured more along the following lines; tspan = ..... y0 = ..... options = ..... [t, ymod...

6 days ago | 0

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Answered
How to plot min and max values on graph
If you meant you want to highight all the peaks and troughs then the following will do it (assuming you haven't got the findpeak...

7 days ago | 0

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Plotting a rankine half body
Try this m=3; %strength U = 20;%positive x-axis %Mesh for fourth quadrant and corresponding stream value function [X1,Y1] = ...

7 days ago | 1

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