Questions on the analytic and numeric equation solving functions of Mathematica (Solve, Reduce, NSolve, FindRoot, DSolve, RSolve, etc.).

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3
votes
4answers
78 views

Constructing a matrix of solutions using findroot

I would like to solve the following equation numerically: Sinh[y]-(y+Tanh[x])Cosh[y]-y Sech[x]^2==0 I would like to do it by creating a list of x values: ...
0
votes
1answer
45 views

Solve equations and express with specific varible

I have two equations as below: eq1: $8 \pi \gamma r-\frac{4 \pi \text{Delta$\_\mu $} r^2}{\text{v$\_$c}}=0$ eq2: $\text{Delta$\_\mu $}=\text{K$\_$b} S T$ When I try ...
1
vote
1answer
59 views
3
votes
1answer
112 views

Randomly generate points on a van der Waals surface

I'm looking to randomly place an atom $\mathbf{A}$ onto a van der Waals surface formed by atoms $\mathbf{B}$, such that the distance between the randomly-generated atom $\mathbf{A}$ and the nearest ...
3
votes
0answers
100 views

How to solve partial differential equation

How to solve in Mathematica this partial differential equation: $0.5\frac{\partial t(x,y)}{\partial x}+1.5\frac{\partial t(x,y)}{\partial y}+t(x,y)=y\cdot \sqrt{1+x^{3}}$ with condition $t(1,y)=y+2$? ...
1
vote
2answers
43 views

ParametricNDSolve and NDSolve inside Manipulate environment

I have a system of three coupled differential equations that can be pretty readily solved by NDSolve: ...
5
votes
4answers
192 views

How to find a starting value that is closer to the solution?

I am trying to solve the following system. Firstly I have a table of numerical values I will call numbers ...
0
votes
1answer
78 views

solve equations

I want to find the solution of these equations: ...
2
votes
4answers
241 views

solve equation with loop

I want to solve equation with different variable and list answers in a table how can Solve it in a loop (Without repeating the equation) ...
1
vote
1answer
74 views

How to input equations for Solve

I'm trying to input: $$\log_{\sqrt 3}\frac{7-2x}{x+3}-\log_{\frac{1}{\sqrt 3}}(x+3)=\log_{\frac{1}{3}}9$$ My try: ...
5
votes
1answer
64 views

How to solve an equation system whose equations are based on Mod[x,y]

I'm trying to find the parameters of a specific linear congruential generator (pseudo random number generator) based on a list of the first five numbers generated by it. The list is this one: ...
1
vote
0answers
169 views

Help with calculating a complicated integral

Edit: The question is solved : )) Thank you for your attention ! I am sorry for mass questions, but the question bothers me a lot. So I would like to ask this question here. This problem arises when ...
4
votes
2answers
68 views

Find Instance with Set Membership Condition

Given two vectors $u=(x_1,\ldots,x_n,a_1,\ldots,a_s) \in \{-1,1\}^{n+s}$ and $v=(x_1,\ldots,x_n) \in \{-1,1\}^n$ and a bunch of fixed vectors $c_1,\ldots,c_k \in \{-1,1\}^{n+s}$ and $b_1,\ldots,b_k ...
3
votes
2answers
71 views

How do I find the intersection points of two piecewise functions? [closed]

I've got a piecewise function that is defined as follows: ...
2
votes
1answer
113 views

Problem with implementing Regula Falsi [closed]

I checked the "Questions that may already have your answer" and didn't really find what I need. It's actually pretty basic. I want to solve an equation manually with Regula Falsi. I dont need a ...
6
votes
3answers
71 views

Using Select on a 2d table with a criteria that accepts 3 parameters

I have a table sets := Table[{i, j, k}, {i, 1, 10}, {j, 1, 10}, {k, 1, 10}] and I want to use a function that accepts three parameters and returns a boolean, as ...
-1
votes
1answer
100 views

Solve failing to solve system of two polynomial equations

I have two equations: $$P_a=P_a(x,y)$$ $$ P_b=1-P_a(x,y) $$ $P_a$, $P_b$, $x$ and $y$ are probabilities so their values are between 0 and 1. If I know the values of $x$ and $y$ I can calculate ...
1
vote
0answers
80 views

Can equation solving be done in parallel?

I'm solving a set of equations that look like: ...
1
vote
0answers
95 views

Solving a set of trigonometric equations

I've been trying to solve the following equations in order to plot Subscript[θ, 41] with respect to Subscript[θ, 2] from 0 to ...
0
votes
0answers
37 views

Using NSolve for Elliptic Equations over Fundamental Parallelogram in Complex Plane

I'm considering solving elliptic functions over a fundamental domain of the torus with half-periods $\omega_{1}=\pi/2$ and $\omega_{2} = \pi \tau /2$, where $\tau$ is the modular parameter of the ...
0
votes
0answers
74 views

How can I solve this system?

Can anyone help me? Consider, with H > 0 ...
0
votes
1answer
37 views

Solving a trigonometric equation for all $x$ using constant coefficients

I want to find the coefficients $a$, $b$, $c$, etc. that make an equation like $a+bx=x$ true for all $x$, but for trigonometric functions of $x$. For example ...
0
votes
1answer
54 views

Shooting method — why is NDSolve giving me an error message?

I am currently trying to write a code to implement the so-called shooting method (I've given a brief description of it below, for those unfamiliar) for second order ODE's in the form ...
0
votes
1answer
53 views

How can I solve NDSolve with a parameter?

I'm a new user and I have no idea how to solve the equation with a parameter by using NDSolve. For example consider following differential equation (DE): ...
1
vote
2answers
121 views

Solve of cubic and quartic equations too slow

In my problem I have a third order algebraic equation for the variable sigma, all other letters are parameters. Here is it's right-hand side, left hand side is ...
2
votes
2answers
61 views

How to find variable values that make an expression divergent or undefined?

How can I find all the values of a variable at which a given expression diverges or becomes undefined? Example: expr=1/(1-x^2); Desired result: ...
0
votes
0answers
42 views
2
votes
2answers
68 views

Solving a linear system of symbolic variables and symbolic parameters

I am trying to run the following code to solve a system of 4 equations. ...
1
vote
2answers
81 views

Solve an algebraic equation

I want to obtain some positive x and y which satisfy the equation 0.01x^2-0.01x^3-0.01x+0.01x^2+y=0 I have written: ...
0
votes
1answer
72 views

Solve doesn't give me all the solutions I expect

I have a problem with Mathematica 10, and I really don't know what's happening here. I try to plot some orbitals and then solve a simple equation. But Nathematica only gives me one the solution, ...
2
votes
1answer
107 views

How do I make Mathematica show me the solutions that it has found while it is searching for them

How do I make Mathematica show me the solutions that it has found while it is searching for them, specifically in this: ...
0
votes
1answer
43 views

Output of Coefficientrules into Jacobian matrix

I have a pair of large polynomials in u, v, a1...a9 and b1...b9, generated by ...
0
votes
0answers
64 views

Speed up the Eliminate

I have problem of eliminating some variables from a set of equations, which contain logarithmic function, in order to obtain a differential equation. These are the parameter and functions in ...
-1
votes
1answer
54 views

Solve Numerical Equation [closed]

I want to find $x\in \ \mathbb{Q} $ such that the first ten digits of $ x \pi $ are 1.234567890. I tried: ...
1
vote
1answer
73 views

Plotting data from a Table in Mathematica

I have been able to solve some differential equations using Tables. The code works fine without errors. However, I am unable to plot the results. Any help would be appreciated. ...
1
vote
3answers
94 views

Find all solutions which satisfy the given conditions

Let $$ m=9n^3+30n^2-9n $$ where $n \in \mathbb{Q^{+}}$ and $m \in \mathbb{Z} $ . Find all solutions which satisfy the given conditions. So I've tried to solve this manually and I was ...
1
vote
1answer
99 views

Wrong root when using numerical values

I have the following inequality: $$ \sqrt{\frac{a}{2x}}+ \frac{b}{1-\frac{a}{a+\sqrt{a(2bx + a)}}} + \frac{a}{2x\frac{a}{a+\sqrt{a(2bx + a)}}\left(1-\frac{a}{a+\sqrt{a(2bx + a)}}\right)} < f $$ on ...
1
vote
1answer
340 views

How to code the following in Mathematica

How do I get the following into Mathematica, solving for a: $$ 0.7 = 1 - \frac{2}{a} \times [ \frac{1}{a} \int_0^a \frac{x}{\exp(x)-1} dx + \frac{a}{6} - 1] $$
1
vote
1answer
58 views

Improving strategy to solve this constrained root-finding problem

I am looking for roots of the function eqs defined below. It has $2k$ unknowns and returns a vector of $2k-1$ components. The sole purpose of the following block ...
0
votes
0answers
27 views

Solve involving simple cancellation on both sides fails when there are too many constants

I've been working with a number of equations of the form x = A * B * x ^ C where I need to solve for x--basically, equations ...
0
votes
1answer
80 views

Nonrectangular tensor encountered [closed]

I am trying to solve a system of equations which characteristic matrix: ...
0
votes
0answers
40 views

Probleme with Ted Ersek's RootSearch package [duplicate]

The following question is a logical continuation of this one. The Ted Ersek's RootSearch package doesn't work with this code: ...
0
votes
3answers
122 views

Manipulation linear systems of equations

I have the following system of equations: i1 = ix - β*ib; i2 = (β + 1)*ib; i3 = ix + ib; vx = i1*Rc + i3*Rb; v1 = i2*Rϵ + i3*Rb; v1 = -ib*rπ; I tried using: ...
2
votes
0answers
87 views

Solving this system of nonlinear equations

Edit Interestingly, I realized solving my problem with $2n$ equations appeared to be more efficient than using mathematical results on the solutions to reduce the problem to $n$ equations (the $n$ ...
1
vote
1answer
81 views

Help with findroot optimization

I'm trying to solve the set of coupled equations $$\frac{-N -2( \lambda + N(\frac{\beta}{\epsilon}-\lambda))\upsilon_l + N ...
3
votes
2answers
83 views

Show Factorial instead of Gamma in the result of RSolve

Now I wanted to solve for a recurring function with RSolve. Here's how I tried: ...
3
votes
0answers
112 views

Complex boundary conditions and NDEigensystem

I am having difficulties implementing a Neumann value when numerically solving the Navier equation using NDEigensystem. The Navier equation is given by $\nabla^2 \vec u + (p^2 - 1) ...
0
votes
1answer
72 views

Invert and fit implicitly defined curve

I need to fit an implicitly defined curve. I thought I could get some data out of Solve, and then using FindFit. Therefore, I ...