All Questions
Tagged with equation-solving mathematical-optimization
211
questions
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Using FindArgMax in NSolve with dependant variables
I have a function for a current through a series circuit containing a capacitor(c) and a resistor(r) and a battery(Ebatt) when the capacity increases from c0 to c.
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0
votes
1
answer
66
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`Minimize` with conditions on `Integers` does not find a correct answer
I want to find the minimum m which satisfies conditions as below:
Minimize[{m, m > 0 && Mod[m 3.1, 0.5] == 0}, m, Integers]
(* {1., {m -> 1}} *)
...
- 886
1
vote
1
answer
88
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Plot "Findroot" with very complex variables
I ran into an extremely complex "zero problem" and don't know how to solve and plot it. Can anyone help with this, please? [Pi]s and [Pi]r are objective functions, pd, po, qd, qo, and [Phi] (...
- 31
2
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59
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How to find the regions for which the derivative of my function changes sign?
I have an energy function of the angles of the electrons' spins. th1 is vector with (2l+2) elements and each element represents the angle of an individual electron spin. I need to eventually find the ...
10
votes
2
answers
1k
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Problem with optimal control and Pontryagin's maximum principle
For dynamic system:
$\dot{x}=\frac{df}{dx}+u$
where $f=e^{-x^2}$
It is necessary to develop optimal control, minimizing criterion:
$J= \int_{0}^{t_f} ((\frac{df}{dx})^2+u^2) \,dt $
Algorithm:
We ...
- 2,444
1
vote
1
answer
99
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Optimization of second order ODE with more than one parameter
I want to optimize a second order ODE with more than one variable:
...
- 91
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45
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can not replace when use ctrl+f
I have a very long output, therefore, I want to find and replace some repeated expressions with abbreviations using crtl +f in Mathematica. when I enter expressions, the mathematical can find it and ...
- 1
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votes
1
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129
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How to solve two implicit functions with two variables and parameters
I have two functions given as;
u[c_,d_] := Sinh[a b^2 c^2 + 3a b d] and v[c_,d_] := Log[a b^2 c^2 + 3a b d + d^2] - d. I want ...
- 31
1
vote
1
answer
75
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Using ContourPlot3D to fine the local extrema of a 3D function
This answer shows a neat way of using ContourPlot and MeshFunctions to find the local extrema of a 2D function: the ...
- 1,472
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39
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Assume some expression is false
I need to Reduce a complicated function and I want to exclude some conditions A and B. How do I assume that the expression A is ...
- 123
2
votes
2
answers
219
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Minimization using NMinimize
I have a system of ODEs say
$$x'(t)=2 x(t)-x(t)y(t)-3 x(t) g(t),$$
$$y'(t)= y(t)-2 x(t)y(t)- x(t) g(t)$$
with ICs $x(0)= 1, y(0)=1/2$, say, for $t_0 \leqslant t \leqslant t_f$, where $t_0$ and $t_f$ ...
- 21
1
vote
1
answer
73
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Finding the joint domain for a couple of functions of three variables
I have two functions $f_{1}(x,y,z)$ and $f_{2}(x,y,z)$ defined respectively as
...
0
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0
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29
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NArgMin with Root functions
I'm trying to minimize an error function sumt to find some parameters S, s0, si :
...
- 1,285
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65
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Fit, NIntegrate in FindRoot results in non-numerical values
I'm trying to find certain values of q for which the derivative of the following function is equal to zero:
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- 115
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47
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NMinimize subject to many complicated conditions not obbeying imposed equation
This question derives from (and refers to) this one asked by me, and I hope that creating a new question rather than editing that one is appropriate. There I ask for a way to find the subset of the ...
- 405