Questions tagged [implicit]

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votes
3answers
132 views

Solving implicitly a trigonometric equation

I am trying to solve this equation with respect to L: L== ((9.81*T^2)/(2*Pi)) Tan[2Pi*d/L] Since you have the unknown ...
3
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1answer
123 views

A system of ordinary differential equations is being recognized as a DAE

I want a function auxiliarfunction that depends on two variables: ρh and ν. I need to plot ...
0
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1answer
106 views

Problem with NDSolve regarding initial conditions of the derivative of a parametric function

I have a function functiontoplot defined using the following piece of code: ...
0
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1answer
75 views

Branches of a curve defined implicitly

I have the variable functiontoplot, defined using the following piece of code: ...
0
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0answers
115 views

Plotting a curve defined implicitly

I have defined the function functiontoplot using the following piece of code: ...
1
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0answers
54 views

Implicit function in an ODE when using DSolve

I'm trying to solve an ODE with DSolve. The problem I'm facing is that in the ODE there appears an implicit function of the variable r*. The equation I'm trying to solve is ...
2
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2answers
170 views

Plot the intersection of random half-spaces

The code ...
2
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1answer
77 views

Problems plotting ImplicitRegion

I have run into some rather strange behavior regarding plotting over regions defined by ImplicitRegion. I have a condition given by ...
4
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1answer
87 views

Imaginary variables in ImplicitRegion

I am using the function ImplicitRegion[]. RegionPlot[ImplicitRegion[x^2 + y^2 == -1, {x, y}]] which gives me a circle, though in the documentation variables are ...
3
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0answers
72 views

Sweep, scale, and rotate implicit 3d region or contour plot along an arbitrary curve

Suppose I have a 3d region or contour that is implicitly defined and has no explicit parameterization. This is easy to plot, as RegionPlot3D and ContourPlot3D allow implicit functions. But now I want ...
1
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2answers
89 views

Finding the arc length of a region defined implicitly with an interpolated function

I begin by defining an interpolation of some data I have stored at this link for brevity. The interpolating function is a function of two variables, x and ...
1
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1answer
76 views

Composition of implicit functions

Let me explain what i have been doing so far. So I want to find an numerical solution or at least a grafic solution to this equation: ...
1
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0answers
47 views

DSolve: lack of implicit option (unlike Maple's dsolve built-in option)

I am working with the book 'Differential Equations for Engineers' (Cambridge University Press). The author dedicates one chapter of the book in solving ODEs with Maple. The book was published in 2010. ...
1
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0answers
66 views

How do I plot two normalized variables with one varying parameter as a 2d plot or a contour plot?

I'm trying to replicate a plot that has both (x,y) normalized variables, I've tried using Evaluate and Contourplot with no success. I have set Rn=20, but it should be another variable. Where Fn=fs/fr, ...
1
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1answer
72 views

Improve performance of evaluating over an implicit region

Consider the following implicit region: ...
0
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2answers
69 views

Implicit differentiation such that I an numerically solve an equation [closed]

If I have some function: N(t) = N0e^(bt) where b is a function of N(t). How do i calculate dN/dt? It gives me a recursion warning since it's just caught in a loop of substituting in N(t) into b over ...
3
votes
3answers
260 views

Plot involving an implicit function

I'm trying to make a plot that depends on an implicit function. This example illustrates the problem: plot $c=2l +n$ in the $c \times l$ axes, where $n$ is implicitly determined by $n^5+ 2n = c^2$. ...
3
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2answers
175 views

Solving the Shifted Neutral Axis Problem

Problem Description: In solving the "Shifted Neutral Axis" method for the stress distribution of a vertical steel vessel supported on a concrete foundation, we can derive the following ...
0
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2answers
90 views

Plot implicit polar equation streamlines

I'm trying to plot streamlines of Stokes solution to an sphere, the expression of streamlines is I've seen similar questions before and this what I have tried As you can see, a=1, U=1, but it seems ...
2
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0answers
81 views

Large system of implicit differential equations

We are trying to solve a large system of implicit system of differential equations for complex variables $\boldsymbol{\alpha}\left(t\right)$ and $\boldsymbol{\lambda}\left(t\right)$. System consists ...
3
votes
1answer
235 views

Solve transcendental equation involving a built-in function [closed]

How can I solve an equation of the following form? $$x = 10+\mathrm{\mathbf{PrimePi}[x]}$$ where $x$ is an integer. I am using Solve but am getting the following ...
1
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2answers
72 views

Interval arithmetic and implicit function inside test

I has implicit function and square region. I need to check this region for presence of part of curve, with interval arithmetic only. My attempt: ...
3
votes
1answer
359 views

Can we convert any parametric equation to implicit form?

The Archimedes spiral equation in parametric form: fx[t_] := Cos[t]*t; fy[t_] := Sin[t]*t; How can it be converted to implicit form? Is there a general method ...
9
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1answer
855 views

How can I find a parametric equation for an implicit surface?

I need a parametric equation for the Taubin heart surface, which is defined in implicit form. I asked a similar question in math branch, but didn't get an answer. This is the implicit form: $$\\\...
0
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1answer
33 views

How to plot the absolute values of the solutions to a parametric equation versus the parameter?

Mathematical formulation of my problem: Let $\Theta\subset\Bbb R$ be an interval. For each $\theta\in\Theta$ let $f_\theta: \Bbb C\to\Bbb C$ be some function and $z_{\theta,1},\ldots,z_{\theta,n(\...
1
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1answer
108 views

Solve implicit equations, input and plot the solution in a different equation

I have two implicitly defined variables, $\sigma_D$ and $\sigma_M$ one of which is a function of the parameter $v$. In particular, $\sigma_D = F(\sigma_D,v)$ where $F(\sigma_D,v)=0$ if $ c_D < -0....
1
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1answer
173 views

How to get the implicit solution of this PDE (Maple can but I don't manage with mathematica)?

I asked this question about the analytical solution of the PDE: $$\partial_t c=\partial_x((c-a)(c-b)\partial_xc) $$ And I was given the answer that Maple gives the following implicit form as a ...
0
votes
1answer
41 views

How can I get paired coordinates from the implicite function?

I have equation E^y = x. How can I use Mathematica to solve all of "y" from the desired "x" value. For example, I want to solve for "y" from x = 0.5 , 1 , 1.5 , 2 , .... , 9.5 , 10. The solution ...
2
votes
2answers
131 views

Solve implicit equations and plot solutions as parameter changes

I have the following two implicit equations that are functions of a parameter $f \in (.5,1]$. I would like to solve these two equations (i.e get $\sigma_D$ and $\sigma_M$) for different $f$ values and ...
1
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1answer
71 views

Determine inverse function with Gröbner basis

I am trying to generalize a way to invert a function using Gröbner basis. My functions are defined in the following form: ...
0
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1answer
287 views

Implicit Function Theorem

I think I am stuck here right now: The exercise is to use implicit differentiation to determine y' considering the following equation: I managed to do this with: ...
8
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2answers
981 views

How to plot a surface from a system of equations? [duplicate]

It seems like a natural thing to do, however I can't seem to find anything on the docs nor here on SE. What I'd like to plot is the locus of solutions to a system of (polynomial) equations, e.g. $$\...
0
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0answers
60 views

How to Solve a Differential Equation System Depending on Variable Solved in an Implicit Function?

I have an ordinary differential equation system need to be solved by using Mathematica. $\frac{dk(t)}{dt}=((1-\kappa(t))k(t))^{\alpha}(1-\frac{\kappa(t)}{\kappa(t)+\frac{1-\alpha}{\alpha}\frac{\eta}{\...
5
votes
2answers
174 views

Holes in ElementMesh with ToElementMesh of ImplicitRegion

I am trying to plot a function in a region below a level curve of the function and within a cell. I have been doing this by calculating an ElementMesh using ...
3
votes
2answers
283 views

Plot implicit region in 3D not working

I'm having troubles plotting an implicit region R (the full expression will be given at the end of this message for sake of readability). This implicit region R is defined by both inequalities and ...
2
votes
2answers
186 views

Multivariate series for approximating implicit system

I'm trying to approximate the solution of an implicit set of equations by means of a Taylor series. I have managed to do so for a solution expressed in terms of a single independent variable, by using ...
0
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0answers
115 views

Implicit derivative of set of equations

I have an equation and I want to take its derivative with respect to two variables. However, it contains some parameters which need to solve them together to find them (Pn, omega, gamma). These ...
2
votes
4answers
182 views

Printing values of y for a range of x for an implicit function f(x,y)

I want to print the values of y for a range of x for an implicit function f(x,y). My equation is f(x,y)=x^2+y^2+2. The range of x is (2,10). I want the corresponding values of y.
1
vote
1answer
169 views

Implicit and Parametric Plot

I am trying to graph the partials of two equations with respect to t, with both equations being implicit. I know I should be getting ellipses with the x-axis as the major axis. ...
8
votes
1answer
208 views

ElementMesh from ImplicitRegion cuts corners of region

I'm trying to define a region within a cell and below a level set of a function using ImplicitRegion and ToElementMesh. Here I ...
0
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2answers
173 views

How to compare ImplicitRegion with empty region?

I have the following function using ImplicitRegion: ...
0
votes
1answer
285 views

How to ContourPlot a two variables (x,y) implicit function with y normalized?

I am trying to use ContourPlot to plot an implicit function. Now I have two variables (x,y) implicit function: ...
2
votes
2answers
69 views

Plot f(x,g(x)) where u(x,g(x))=0 can not be solved explicitly

Suppose $u(x,g(x))=0$ can not be solved explicitly for $g(x)$. I need to plot $f(x,g(x))$. How can this be done? An example: $\frac{1}{\log y}=y-x$ for $x\ge 1$ has a solution for $y$, but can not be ...
2
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2answers
80 views

Incorrect implicit region for function that indexes or sorts a list

I'm having trouble creating a region with ImplicitRegion. In general, I first limit the region to be within a Parallelogram. <...
0
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0answers
67 views

Mathematica giving incorrect result for implicit equation $x^{\frac{2}{3}} + y^{\frac{2}{3}} = 1$? [duplicate]

When I type the following implicit equation into Mathematica I only get 'one quarter' of what the resulting plot should look like, i.e., I only get the upper-right quadrant. ...
1
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2answers
382 views

3D plot over an implicit region gives no answer

I have a function(X,Y) which I would like to plot over an implicit region. ...
3
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0answers
177 views

Errors Using FindFit and FindRoot

I'm trying to fit the following equation to data: where and x and y are the dimensionless variables x=V/Vr and y=Ir/(2*I0). n=1 and I'm trying to find Vr and R. The blue is an example of the curve ...
1
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0answers
29 views

Implicit Root and RegionPlot [duplicate]

Here is my problem: I am trying to RegionPlot; however, I have an implicit root. I tried the following code but it generates an error and does not paint the region I know for sure exits: ""The ...
0
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0answers
129 views

IterationSafetyFactor error in NDSolve

I am solving a set of 4 coupled, nonlinear ODEs using ImplicitRungeKutta in NDSolve. I am running the solutions over many different initial conditions, and for about 20% of solutions, I get the error ...
4
votes
2answers
198 views

Is there a Bug in Mathematica 11.1 with RegionCentroid?

Bug introduced in 11.1 and fixed in 11.2.0 I solved for the centroid of $x^2+y^2+\sin(4x)+\sin(4y)=4$ ...