Community Profile # Alan Stevens

Last seen: Today Active since 2020

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Help with Riccati equation
You haven't defined B (in the function definition)

3 days ago | 0

How to create a time function and make a line rotate at a certain angular speed?
Do you mean something like this? r2_length = 2; tend = 10; % s dt = 0.1; t = 0:dt:tend; omega = 1; % rad/s theta = omega*t...

5 days ago | 0

Cannot get integral function to work for two limits
Try this %Enthalpy datum conditions (Kelvin) Ti=(25+273.15); %Input temperature (Kelvin) T1=(183+273.15); %Output tem...

6 days ago | 0

I have some errors in executing the following code, can anyone help me please?
You have no initial guesses for y(5) and y(7). And what about y(6)?

22 days ago | 0

How can I plot a diagram with 12-15 different colors
Specify the colors with RGB triplets. doc Color

1 month ago | 0

This code give me an error of Index exceeds array bounds.
More like this? m=60; g=9.81; k=80; m_2=10; m_1=15; h=100; w=15; t=1:10:100; x = zeros(1,numel(t)); for i=1:numel(t) ...

1 month ago | 0

Why does MATLAB grader refuses to get my answer with the double integral evaluation problem?
As follows Oops! I did the sum incorrectly! Should have been like this: % box side length delta = 0.01; % mid box points...

1 month ago | 0

initial condition vector longer than ODE vector?
Do it like this: a=2; b=5; % v0 is now set to 10 v0=10; % Using a,b to determine rest of variables R=10*a; C=0.0001...

1 month ago | 1

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Can some one fix this code? I am unable to understand this code? Though fixing one problem another problem is arising ! please help!
In the following line: G = (randn(Np,Mtot)+1j*randn(Np,Mtot))/sqrt(2); % When i=1, G is 1x20, but H is 20x2 so the following l...

1 month ago | 0

Connect all dots I polarplot
Like this? r=[10:36:360 10]; r = r/360*2*pi; s=[5,3.5,5,4,4,3.5,4,4.2,4.7,4, 5]; polarplot(r,s,'-x')

1 month ago | 0

I dont understand this error in line 653 and the end goal is to make a graph
Get rid of the gaps between Consibio and Cloud, and between Cloud and Datalog (In the file name and when calling it).

2 months ago | 0

How can I solve the following PDE?
Try setting tau = T - t, so that dA/dt = -dA/dtau etc, and A(T) , B(T) become A(0), B(0). i.e. turn the boundary value problem ...

2 months ago | 0

how to use ode45 to solve motion equation with Matrix
Does this help? %% Data M =[ 0.0210 0.0014 -0.0209 0 0 0 0 0 0.0014 ...

2 months ago | 1

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Subscript indices must either be real positive integers or logicals always show up. what should i do?
Well, this works, but you might want to check the correctness or otherwise of your mode_shape calculations (there are a lot of z...

2 months ago | 1

incorrect number or types of inputs or outputs for function 'int'
Replace your power calculation with power = (1/T_0) * trapz(t,y.^2); Edited - Walter is correct.

2 months ago | 0

Regula-falsi Method that keeps running
Brackets!! f = @(x) 2.^x - x.^2 - 2; % Function whose roots are desired xL = 4; xU = 5; % Initial guesses Tol = 1...

2 months ago | 0

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Trying to answer a math problem using newton's method but having problem in the function.
Matlab doesn't like implied multiplication (x ^ 2)z should be (x ^ 2)*z etc. Also, in Matlab log(x) is ln(x)

3 months ago | 0

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How to set multiple values of a threshold?
Here's one way: tolX1_4 = [1 1 1 1 1 -1 1 1 0 1 1 1 1 1 1 1 1 ...

3 months ago | 0

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Here's a numerical approach: First manipulate the equations tspan = [0, 120]; ic = [80000, 0.001]; [t, xy] = ode45(@rate, ...

3 months ago | 0

how ode solver works
doc ode45 Go to the References section. The two references listed will supply you with all you need to know about the ode solv...

3 months ago | 0

Solve Differential Equation with initial conditions and function
Try modifying your if statement in Moment. Something like if x<a V =...; M = ...; elseif x>=a && x<L M = ... ...

3 months ago | 0

problem in creating function file using ode45
Are you looking for something like this? (I might have misinterpreted your equations!) O=1; a=pi/2; g=9.81; L=100; tspan ...

3 months ago | 0

how can eliminate negative data in erf function?
Should term2(i) = (sqrt(lemdaD)./(2.*e1(i))).*exp(-(v1(i).*sqrt_avgsnr - v2(i).* mu).^2./(2.*e1(i).^2)).*.... erf((e4(...

3 months ago | 0

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Why is my plot not showing for improved Euler method?
You need to keep track of each step. Your original simply overwrites the values of t and y at each step. dy=@(t,y) -(0.1/10^(1...

3 months ago | 1

Why I couldn't plot this graph f=(@(x,y) (x.^2)+(x*y)+(y.^2)<=68200.^2/3);
This will give you the outline (I've assumed you want 68200^(2/3) rather than 68200^2/3) f=@(x,y) x.^2+x.*y+y.^2-68200.^(2/3); ...

3 months ago | 0

I want to solve a simple "y=mx+c" with initial condition to find value of "m" and "c" but i am getting error by using following code. Any idea to tackle this kind of problem?
These are simple linear equations in m and c so set: X = [x(1) 1; x(2) 1]; Y = [y(1); y(2)]; and solve using X\Y to get m a...

3 months ago | 0

I have been trying to code a solar pv module for 1 diode model, the following is my code, can someone tell me the mistake ive made and the correction to it pls.
Like this? Note: I've made kref positive to avoid the I's being complex. This might be completely incorrect!! Pmpp = 50; ...

3 months ago | 1

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Reorganization of data in matrix
Like this? M = [1 1 0.270588872500870 1 1 0.191034400222846 1 1 0.316821350897659 1 1 0.391794699189989 1 2...

3 months ago | 0