Answered
second order differential equation with variable coefficients
Write your equation as a first-order system y1'=y2 y2'=(-k*y1+F(y1))/m use "interp1" to interpolate F(y1) from your k...

9 years ago | 0

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Answered
compare function values with constant
Why don't you simply calculate chi2cdf(LR2,1) ? Best wishes Torsten.

9 years ago | 1

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Answered
How to solve this Algebraic integral with limits
You should use a numerical solver for this integral. Use "integral". Best wishes Torsten.

9 years ago | 0

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how to write equation in matlab ??
I=@(x) s(x).*sin(2*pi*f*x); plot(x,I(x)) Best wishes Torsten.

9 years ago | 2

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Answered
PDE solver without PDE solver toolpack
If 1d is enough for you, you can use "pdepe". Otherwise, you will have to do the spatial discretization on your own and solve...

9 years ago | 0

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Integrating with no variables
If you want to integrate the constant function f2(x)=-log(b+0.01)+exp(b), just define it this way: f2=@(x)-log(b+0.01)+exp(...

9 years ago | 0

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Solution is going to infinite iterations
Your decision variable in the while statement must be abs(fx)> err and/or abs(x1-x)>err but not abs(x1-a...

9 years ago | 0

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Issues with solve. Cannot solve symbolically. Returning a numeric approximation instead.
As written, your equation reduces to a(i)*(-cos(asol)*asol + sin(asol))-cos(asol)*pi==0 where I renamed the solution var...

9 years ago | 0

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What are the distribution functions of the gamma distribution shape and scale parameters?
Use gamfit. It gives you confidence intervals for the estimated parameters. Best wishes Torsten.

9 years ago | 0

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Answered
Double integral with one integral having limits as a function of other variable
Directly evaluate "A" and insert the expression in "fun_Z0": http://www.wolframalpha.com/input/?i=integration&rawformassumpti...

9 years ago | 0

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solve difference equation in matlab
A quite complicated way by using "ztrans" and "iztrans": <https://books.google.de/books?id=nPTw5B8P3OAC&pg=PA392&lpg=PA392&d...

9 years ago | 0

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Answered
Best/fast approach to solve two coupled differential eigenvalue problem
Maybe the example "Compute Fourth Eigenvalue of Mathieu's Equation" under https://de.mathworks.com/help/matlab/ref/...

9 years ago | 0

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Imagenary results while using solve while requesting only Real solutions
help real help imag Best wishes Torsten.

9 years ago | 0

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I am trying to plot this function y=(1/2)*(1+(sqrt((2920)*(log((100)/(100-x)))+1))) but getting errors?
Use y=1/2*(1+sqrt(2920*log(100./(100-x))+1)); Best wishes Torsten.

9 years ago | 1

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Answered
solving system of ode-error in results
Check f(x(n),y(n)), g(x(n),u(n)),k(x(n),v(n)) and l(x(n),w(n)) in the corresponding loops. You will find that the functions r...

9 years ago | 0

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Solve a set of implicit equations
help fsolve Best wishes Torsten.

9 years ago | 0

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How to Solve a Highly Non-Linear PDE in Matlab
Try "pdepe" with m=2. It uses the method-of-lines approach based on a FEM discretization with a stiff ODE integrator in the b...

9 years ago | 0

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need help to find the solution of 4d equation
Try "fsolve" on the system of equations given by (A97)-A(100). Best wishes Torsten.

9 years ago | 0

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using fmincon function for optimisation
[xalpha,fval,flag]=fmincon(gap,xalphakeep,[],[],[],[],alphamin,alphamax,@nonlconstr,options); alphamin and alphamax must be ...

9 years ago | 0

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Answered
How to solve simultaneous Ordinary Differential Equation
k1 = ...; % set constant k1 k2 = ...; ...

9 years ago | 1

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Answered
I get matlab error :Failure in initial user-supplied objective function evaluation. FMINCON cannot continue.
1. Input vector for the objective function F is only x, not x and xdata. 2. I don't see that you define "xdata". 3. Sinc...

9 years ago | 0

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Answered
Plotting a Weibull density function
Try x=0.1:0.1:130; instead of x=0:0.1:130; Best wishes Torsten.

9 years ago | 1

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Answered
coupled ODEs with two variables solver
This is a hyperbolic system of 1st order partial differential equations. If you have the NAG toolbox, there are solvers for t...

9 years ago | 0

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Matlab says that the 'e' is undefined
See the examples under https://de.mathworks.com/help/symbolic/int.html Best wishes Torsten.

9 years ago | 1

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Find the constant of a cubic function
All cubics of the above form with A+B=0.845 have f(0)=0 and f(1)=0.845. A and B are not uniquely determined b...

9 years ago | 0

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How to solve simultaneous Partial Differential Equation
These are ODEs, not PDEs. Use a solver from the ODE-suite (e.g. ODE15S). Best wishes Torsten.

9 years ago | 0

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Answered
Solving differential equation containing independent function
The example "ODE with Time-Dependent Terms" under https://de.mathworks.com/help/matlab/ref/ode45.html shows you how ...

9 years ago | 2

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Answered
Usage of 'dsolve' function in MATLAB
"dsolve" can be used for ordinary differential equations (1 independent variable). Your equation is a partial differential eq...

9 years ago | 0

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Optimize for multiple variables in nonlinear function
min: sum_{i=1}^{t_final} Power_inserted(i)*Price(i) s.t. L(t_final)-1=0 Unknowns are Power_inserted(i) (i=1,......

9 years ago | 0

Answered
How do I constrain a vector's value within a nonlinear fit?
Put them in the fittype equation as parameters-squared. Best wishes Torsten.

9 years ago | 0

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