Questions tagged [implicit]

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54 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
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1answer
70 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 ...
8
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1answer
462 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: $$\\\...
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1answer
25 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(\...
0
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1answer
76 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
114 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
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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
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2answers
83 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
61 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
107 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
476 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. $$\...
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0answers
49 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
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2answers
133 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 ...
2
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2answers
142 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 ...
1
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2answers
141 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 ...
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0answers
77 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
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4answers
114 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.
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0answers
36 views

How to plot a complicated implicit function?

For example, I have an expression kg=const. p = p(D) and D is an implicit function of omega alpha1, mu = const Is it possible to plot expression beta(omega) using ContourPlot?
1
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1answer
92 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
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1answer
145 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 ...
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2answers
87 views

How to compare ImplicitRegion with empty region?

I have the following function using ImplicitRegion: ...
0
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1answer
148 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
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2answers
67 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
74 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. <...
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0answers
65 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
159 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
86 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
26 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
93 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
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2answers
191 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 $x^2+y^2+\sin(4x)+\sin(4y)=4$ ...
7
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3answers
316 views

How to Discretize the Following Region Using Reasonable Bounds?

I want to accurately discretize the implicit equation $x^2+x+y^2+\sin(4xy)+\sin(3xy)=3.9$. To get the whole discretized shape, I'm forced to use oversized bounds ...
1
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1answer
217 views

Fitting to the implicit function

I already asked questions about this issue here but there have been some changes that I want to ask a new question. My data is : ...
-1
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1answer
65 views

How can all the data points be extracted from a graph of an implicit function which is plotted using Contourplot? [closed]

I have a plot of an implicit function. I would like to extract all the data points from the graph. The plot is done using contourplot and cannot be plot with plot command.
1
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2answers
60 views

Degenerate graph using ContourPlot

I have this code Manipulate[ContourPlot[x^2 (z + 1) - (x + 1)^2 (z - 3 x^3) == 0, {x, -v, v}, {z, -w, w}], {v, 1, 50}, {w, 1, 50}] to interactively make zoom in ...
2
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0answers
178 views

Fitting to an implicit function

I am trying to fit a data ...
7
votes
1answer
286 views

Length of a curve parallel to a spline

I have constructed a BSplineFunction through a set of random points: ...
8
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0answers
88 views

How can I plot a region parametrized by another region?

I am trying to learn how to describe and plot a 2D-region for $x_1$ and $x_2$ based on / parametrized by another 2D-region for $v_1$ and $v_2$. In the following example, the region ...
0
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1answer
132 views

Derivative of an Implicit Function

So I'm having a bit of an issue in trying to take the derivative of an implicit function. The problem I'm trying to solve is this: f(t,y(t)) = y' = e^(t-y) Where ...
5
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4answers
554 views

How to view an ImplicitRegion defined by an equality?

Bug introduced in 10.4 and fixed in 11.0 I type l = 3 r = ImplicitRegion[(x^2 + y^2)^3 == l *x^2* y^2, {x, y}]; RegionPlot[r] and I obtain How could I ...
1
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1answer
512 views

Solve implicit complicated equation

I have to solve the following implicit equation: ...
0
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1answer
984 views

plot a surface using plot3d etc within a sphere

I recently need to plot a 3d function that satisfies certain constraints, like x^2+y^2+z^2<=1 or things similar. So I wonder how to plot the part that only ...
2
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0answers
76 views

Which real part of a function given by an implicit equation should I choose?

I want to plot the real part of function $y(x)$ given by the following implicit equation: $$[y + (e + f x^2)x^2 + 23 x^2](gy + x^2 + 2 \frac{a}{d^2}\ln\frac{1 - b}{1 - c}) =0,$$ where $a$, $b$, ...
8
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1answer
346 views

Integral over an ImplicitRegion

I often need to do integrals over surfaces of different geometries ( in my case it's fermi surfaces ). To do so i use the following code ...
16
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4answers
8k views

How to do implicit differentiation in Mathematica?

I have an equation which is K^(1/2)*L^(1/2)-(K+L) = 24 but I don't know how to do implicit differentiation to find dK/dL because I only know how to do the normal ...
1
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0answers
49 views

Plotting equations stored in a variable [duplicate]

The following produces an empty plot: eqn = x^2 + y^2 == 1; ContourPlot[eqn, {x, -1, 1}, {y, -1, 1}] Whereas the following plots a circle, as expected: ...
4
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0answers
438 views

Integrate function over a 2D implicit surface

I have the following problem. Let's say we have a 2D region, let me be very explicit: ...
1
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4answers
414 views

Implicitly inverting a function from numerical solution [closed]

I have the following piecewise continuous function: ...
2
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0answers
128 views

Why does ContourPlot refuse to draw all 4 quadrants whenever fractional powers are in the implicit function? [closed]

I would like to plot the astroid which is given by: $x^{2/3} + y^{2/3} = 1$ When I use ...
5
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2answers
848 views

Finding minimum and maximum of implicit functions

The equations of the system are ...
4
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2answers
187 views

Unexpected behavior of ImplicitRegion -> RegionPlot

I have two semicircles that are identical except that the second is shifted one unit to the right. ...