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It always gives the error of "Empty sym: 0-by-1"
The result is correct: You have 26 equations of the form 1800 - c(i)*Fe = 0 for one variable Fe to be solved for, but 26 dif...

3 years ago | 0

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error: matrix dimensions must agree
K_a in your function definition is a scalar. Thus you have to change x0 to be a scalar, too. clc close all clear background...

3 years ago | 0

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What is the problem for the following matlab code for drawing contour plots of R0 against two parameters?
alpha= 1.0*0.0241; beta=0.001936 ; gamma=0.0020255; T=23.3; T0=23; mu_ref = 0.0017; mu1=0.039 ;mu2=0.002894; L=8; L0=8 ; delta...

3 years ago | 0

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fmincon is not working
You must define F = @(x) fun(x(1),x(2)) and pass "F" instead of "fun" to fminunc.

3 years ago | 0

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How to integrate a complicated function?
https://www.wolframalpha.com/input?i=integration&assumption=%7B%22C%22%2C+%22integration%22%7D+-%3E+%7B%22Calculator%22%7D&assum...

3 years ago | 0

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Function optimization with some conditions conditions
The dimensions would be correct if you use b = [b1;b2.';b3.']; instead of b = [b1;b2;b3]; but you'd better post the problem ...

3 years ago | 0

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How do you go about guessing for fitting parameter initializations?
This is a linear fitting problem for which you don't need initial guesses for the parameters: Data = [0.006 334 0.011 276 ...

3 years ago | 0

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How to solve a boundary value problem x"+x'=1, x(0)=1, x(1)=2 , with an impulse condition x(i/3+)=2*x(i/3)+1, x'(i/3+)=3*x'(i/3)-1;
syms t x1(t) x2(t) eqn1 = diff(x1,t,2) + diff(x1,t) == 1; Dx1 = diff(x1,t); eqn2 = diff(x2,t,2) + diff(x2,t) == 1; Dx2 = dif...

3 years ago | 0

Answered
Error: In an assignment A(:) = B, the number of elements in A and B must be the same.
w(i)=w; This line of code makes no sense. You want to assign a vector w to a scalar w(i).

3 years ago | 0

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solving complex matrix with symbolic variables
syms a b c d e f g h k real z1=-30j; z2=0.08+0.40j; z3=-35j; z4=0.10+0.50j; z5=0.10+0.50j; z6=-25j; z7=0.30j; p1=a; p...

3 years ago | 0

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Kindly help me out with this code. its urgent please .thanks
The trigonometric functions sin, cos for an argument x are invoked as sin(x), cos(x),... If they have an exponent, they are eit...

3 years ago | 0

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How can I create a spline with conditions on the middle?
% Set up the problem with 16 conditions for 16 spline coefficients syms a [4,1] syms b [4,1] syms c [4,1] syms d [4,1] ...

3 years ago | 0

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Research of inflexion point - Index exceeds the number of array elements.
You forgot to initialize x as x = [] in the second example.

3 years ago | 0

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Fit a statistical distribution to truncated data
Why should it be justified to fit a dataset of a truncated normal by a normal distribution ? pd_fit_trunc = fitdist(data_trunc,...

3 years ago | 2

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Roots of an equation when two parameters are changed
"num" is a polynomial of degree 7 in M. Thus it has seven roots. But your code only gives one of these seven. So I hope you get ...

3 years ago | 0

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Answered
How can i find the roots of the complex equation?
You can get an analytical solution if you substitute y = z^2: syms y p = y^4 + (10548593400*y^3)/42679 + (33343133111071335000...

3 years ago | 0

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How to solve delay differential equations with computed history (not constant)
Save the results of the non-delayed ode in arrays T and Y, create an interpolation function fun_history = @(t) interp1(T,Y,t) ...

3 years ago | 0

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Answered
use of fminimax solver in matlab for optimization
z seems to be a constant in your objective function. Thus it doesn't influence the result of the optimization and doesn't need t...

3 years ago | 0

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Arrhenius model fitting using fminsearch
Your model function σ(T) = σ_ref * exp(-Ea/(kT)) does not have a maximum. Thus it is not suited to reflect your measurement data...

3 years ago | 0

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maximization with fmincon which of the two codes provided do the correct job
I suggest using a function instead of a function handle. I compared it with your implementation and random matrices for W and R...

3 years ago | 0

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Arrhenius model fitting using fminsearch
Imagine you get Ea = 3 and k = 6 in one run and Ea = 12 and k = 24 in a second run. Both solutions give the same quality of fitt...

3 years ago | 0

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Assign a value to a matrix element defined as a variable
prop = @(x)[[x(1)*ones(11,1);x(2)*ones(12,1)],[x(3)*ones(11,1);x(4)*ones(12,1)],zeros(23,1),zeros(23,1)]; prop([1 2 3 4])

3 years ago | 1

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Answered
can find regression and curve fit for given equation
Since your equation can be rearranged as dy/dx = 1/c * log((m-a)/b) your model assumes that dy/dx is equal to a constant that ...

3 years ago | 0

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lsqnonlin - error in finite differences, arrays of incompatible size
The size of your problem changes in the course of the computation from 685 to 650 functions to be minimized (see above). This wi...

3 years ago | 0

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Answered
How to turn off the simplification condition?
Then use expr = simplify(expr,'IgnoreAnalyticConstraints',true)

3 years ago | 1

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Least Squares with constraint on absolute value
rng("default") n = 32; y = rand(n,1) + 1i*rand(n,1); B = rand(n) + 1i*rand(n); x0 = rand(n,1) + 1i*rand(n,1); x0 = [real(x0...

3 years ago | 1

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Answered
Plotting the result of ODE that as a integral component.
For the first one substitute z(t) = integral_{tau=0}^{tau = t} y(tau) dtau and solve the system of differential equations y'...

3 years ago | 0

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Answered
How can I integrate the math equation (attachment) numerically?
Just as it's written: result = integral(@(Ex)Ex.*(NL(Ex)-NR(Ex)).*T(Ex),0,Inf) Of course, I don't know whether you defined the...

3 years ago | 0

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Plot the Diagram of the probability of some data
I don't know what exactly you mean by "Probability Diagram", but the usual way is to use histogram(data,'Normalization','pdf')

3 years ago | 0

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all function B = all(A < 0.5,3)
But why does this yield the same result? Because A has only 2 dimensions, not 3 or 4. Thus "all" operates on all elements separ...

3 years ago | 1