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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...

etwa 3 Jahre vor | 0

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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).

etwa 3 Jahre vor | 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...

etwa 3 Jahre vor | 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...

etwa 3 Jahre vor | 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] ...

etwa 3 Jahre vor | 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.

etwa 3 Jahre vor | 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,...

etwa 3 Jahre vor | 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 ...

etwa 3 Jahre vor | 0

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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...

etwa 3 Jahre vor | 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) ...

etwa 3 Jahre vor | 0

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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...

etwa 3 Jahre vor | 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...

etwa 3 Jahre vor | 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...

etwa 3 Jahre vor | 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...

etwa 3 Jahre vor | 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])

etwa 3 Jahre vor | 1

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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 ...

etwa 3 Jahre vor | 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...

etwa 3 Jahre vor | 0

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

etwa 3 Jahre vor | 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...

etwa 3 Jahre vor | 1

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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'...

etwa 3 Jahre vor | 0

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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...

etwa 3 Jahre vor | 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')

etwa 3 Jahre vor | 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...

etwa 3 Jahre vor | 1

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Unable to solve boundary condition problem
"ode == 0" cannot be explicitly solved for D2y. But given y and Dy, you can try to use Newton's method to supply D2y. Define a...

etwa 3 Jahre vor | 0

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How to ramp a boundary condition in bvp4c
y_0 = 0.1; y_list = linspace(0,y_0,1000); fy_list = y_list.^(1.5); f_inter = @(y)interp1(y_list,fy_list,y); L = 10; n = 100...

etwa 3 Jahre vor | 0

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How to find the point of intersection between three planes in MATLAB
If you don't have a point on the third plane, your problem is mathematically kind of a linear system of three equations in four ...

etwa 3 Jahre vor | 0

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How to calculate real probability of data
Usually, one assumes that the underlying distribution for the realizations in A is continuous. This implies that each element in...

etwa 3 Jahre vor | 2

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What can I do?
y(i,n) = 2*y(i, n-1) -y(i, n-2)+ (c*At/Ax)^2*(y(i+1, n-1)-2*y(i,n-1)+ y(i-1,n-1)); For n = 2 and i = 2, you try to access y(2,0...

etwa 3 Jahre vor | 0

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converting matlab expression into a symbolic expression
syms x y z r R eqn = z == x^2/(2*r) + x^4/(8*r^3) + x^6/(16*r^5) + y^2/(2*R) + y^4/(8*R^3) + y^6/(16*R^5)

etwa 3 Jahre vor | 1

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plotting variables within function
Recalculate Fwx from the solution (see above).

etwa 3 Jahre vor | 0

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