Questions tagged [equation-solving]

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

Filter by
Sorted by
Tagged with
2 votes
2 answers
115 views

FindRoot with input as a list

I have three equations: eq1, eq2, eq3 with variables a,b,d,k. I wish to find the roots of these equations by assuming ...
Math_student's user avatar
-1 votes
1 answer
91 views

Adding Points on an Elliptic Curve

How do I do this in Mathematica? The curve given by the equation $y^2 = x^3 + 29x + 7$ defined over the integers modulo $10007$ Adding the first pair of points $P = (3737, 4549)$ and $Q = (8286, 6097)$...
Bob's user avatar
  • 1
2 votes
3 answers
242 views

Getting all solutions to an equation on condition the variables are either 0 or 1

Given a list of 3-bit binary lists b={{0,0,0},{0,0,1},{0,1,0},{0,1,1},{1,0,0},{1,0,1},{1,1,0},{1,1,1}}; I would like to have all possible solutions to ...
Phillip Dukes's user avatar
1 vote
1 answer
246 views

Numerical solving diffusion equation in spherical coordinates

Mathematica nicely solves Poisson's equation in spherical coordinates as ...
Rodion Stepanov's user avatar
1 vote
1 answer
54 views

First order differential equation with two conditions

I want to produce all possible solutions for this equation: ...
Mathecis's user avatar
  • 153
1 vote
1 answer
63 views

Problems with Solve. Only works for specific parameters. Solve function do not "start"

I have the following problem I want to solve the following equalities. My used code: ...
Tremonia's user avatar
2 votes
1 answer
150 views

How to solve this integral equation numerically?

I am encountering difficulties while trying to numerically solve an equation in Mathematica that involves an unknown function and an integral. Specifically, the equation takes the form of \begin{...
dcmpsr's user avatar
  • 53
2 votes
2 answers
84 views

Selecting Solve results according to conditions

When using the Solve function I get four possible answers. How can I automatically get the option in which x and y are positive? Where to insert the conditions x>=0 and y>=0? ...
Vladimir's user avatar
  • 161
1 vote
2 answers
159 views

How can I choose the integer numbers a, b, c, d, t so that the equation $\sqrt{a x^2+b x+c}=d x+t$ has two integer solutions?

The equation $\sqrt{x^2+36 x+180}=2 x+15$ have two integer solutions are $x = -5$ and $x = -3$. How can I choose the integer numbers $a, b, c, d, t$ so that the equation $\sqrt{a x^2 + b x + c} = d x +...
Rosa_2023's user avatar
1 vote
0 answers
63 views

Why this Solve cannot be solved [duplicate]

Solve[Sum[p*a[i], {i, 1, n}] == 0, p, Reals] Solve[p*Sum[a[i], {i, 1, n}] == 0, p, Reals] The first line of code cannot be solved, but when the variable ...
Yilin Cheng's user avatar
3 votes
2 answers
105 views

Solving A System of Two Implicit Equations

I am solving a system of 6 equations, and I am interested to know the solution for different rhoBar values. Here is the input parameters: ...
Johnson's user avatar
  • 345
0 votes
2 answers
54 views

Can a redundant condition be removed from a solution?

A solution to this equation: Solve[{(p-x)^2 + (q-y)^2==d, p/q==t}, {p,q}, Reals] has this repetitive condition: $\displaystyle\quad d > \frac{x^2 - 2txy+t^2y^2}{...
scriptfoo's user avatar
  • 201
0 votes
1 answer
51 views

How can i create an equation with a sum? [closed]

I have a list of $p_i$ and the condition that $\sum_{i=0}^{i=69} p_i = 1 $ I also have a list of 69 other different equations. I want to use NSolve to solve for the ...
100xln2's user avatar
  • 427
1 vote
1 answer
105 views

How to find the variable $k$ which minimizes the function $\Omega^2$?

$$\Omega^2(k) = 4(\sum\limits_{m=1}^{\infty}\frac{1-\cos(km)}{m^{1+\alpha}})(\sum\limits_{m=1}^{\infty}\frac{1-\cos(km)}{m^{1+\alpha}} - A^2)$$ Let $A = 1$ and $\alpha = 1$ and write $w(k) := \sum\...
KZ-Spectra's user avatar
0 votes
0 answers
55 views

Get curve equation from parametrization

I am quite new to Mathematica and I have been wondering how to do this one very specific thing. I have two functions $x(t)$ and $y(t)$ that are the parametrization of a curve, how would I get the ...
Memat's user avatar
  • 101
0 votes
2 answers
86 views

`Reduce` is running forever

I'm trying to solve the last inequality in Reduce in the code below in terms of rmax under the parameter conditions included in <...
ppp's user avatar
  • 817
0 votes
0 answers
59 views

How to speed up maximization of the Solve output?

I am trying to maximize the solution of the system of algebraic equations for different values of parameters. The problem is related to the absorbing times in Markov chains. Here is the code ...
San's user avatar
  • 1
3 votes
1 answer
150 views

Cannot solve this polynomial equation

I'm trying to solve the following polynomial equation for $x$: $$ (qx)^\alpha (1-qx)^{1-\alpha} = [(1-q)x]^\beta [1-(1-q)x]^{1-\beta} $$ where $\alpha, \beta, q, x$ are all strictly between 0 and 1. ...
raving-bandit's user avatar
2 votes
3 answers
143 views

Multiple solutions from NSolve

I have a list of polynomial equations which I can solve using NSolve. However, it gives me a large number of similar solutions. The solutions are largely identical ...
Hugh's user avatar
  • 16.3k
1 vote
1 answer
70 views

Solving a non-algebraic equation at the symbolic level [closed]

Versions 10, 11, 12, 13.0.0.0 and 13.2.0.0 solves the following system of equations ...
Vaclav Kotesovec's user avatar
1 vote
1 answer
68 views

Newton Raphson apply to Van der Waal Equation

I need assistance with this problem. I have two functions, where f1 corresponds to the dimensionless van der Waals equation of state, and function 2 corresponds to the dimensionless chemical potential ...
Larissa Santos's user avatar
1 vote
1 answer
65 views

Find an instance satisfying equation

I have the following equation with two variables xi and nu. ...
Dotman's user avatar
  • 424
0 votes
1 answer
30 views

Solving Nonlinear Algebraic Equation

What is wrong with the code below? Mathematica is taking a long time trying to solve it. ...
Jose Lockhart's user avatar
0 votes
1 answer
74 views

Solving inequality with `Reduce` doesn't work

I'm trying to solve an inequality in terms of one variable under some conditions for parameter. Here is the code. ...
ppp's user avatar
  • 817
0 votes
1 answer
122 views

Newton-Raphson Method Errors

I need assistance with this problem. I have two functions, where f1 corresponds to the dimensionless van der Waals equation of state, and function 2 corresponds to the dimensionless chemical potential ...
Larissa Santos's user avatar
2 votes
2 answers
189 views

Real zeros of complex function

I must find the zeros of a complex function $\xi$ that depends upon two real variables $B$ and $k$. The function is obtained by evaluating the determinant of the identity matrix of dimension $2n$ ...
Dario Bercioux's user avatar
1 vote
0 answers
71 views

How to solve differential equations in just in reals? [closed]

I am working on a variation problem: My goal is to find the curve that connects a point $(x_1, y_1)$ to another point $(x_2, y_2)$. When this curve is revolved around the x-axis, it should generate a ...
Zhang Xuan's user avatar
0 votes
2 answers
122 views

Limit the number of the results returned by Solve to some specific number

I have this Solve: ...
Dani's user avatar
  • 3
1 vote
2 answers
131 views

How to solve this integro-differential equation in Mathematica?

I am a new user of Mathematica, and I am trying to figure out how to solve the following integro-differential equation in Mathematica: $\frac{\partial c(x,t)}{\partial t} = -2 \mu x c(x,t) + 4 \mu \...
Matt's user avatar
  • 11
0 votes
1 answer
130 views

Solve[] isn't producing a correct result

I want to find the exact algebraic roots of the following function in terms of Z, P, Q, <...
Lawton's user avatar
  • 103
0 votes
1 answer
61 views

Is it possible to get rid of the square root in the solutions of the following symbolic quadratic equation?

I have a quadratic equation, which I want to solve, but don't want the square root to appear within the solutions. I tried converting the discriminant into a quadratic form but failed, not sure if ...
larry's user avatar
  • 715
0 votes
0 answers
59 views

How does Mathematica select principal roots of complex numbers?

When I do I^(1/3) I get Out[]:= (-1)^(1/6) which is one of the solutions of $z^3=i$. There are two more solutions which are ...
sam wolfe's user avatar
  • 4,613
3 votes
1 answer
154 views

Solving system of first order PDEs

I am trying to solve the 1st order PDE system \begin{align} \xi_u^2+\eta_u^2&= \left(1+\frac{\xi^2+\eta^2}{4} \right)^2\\ \xi_v^2+\eta_v^2&=\left(1+\frac{\xi^2+\eta^2}{4} \right)^2 \end{align} ...
Daniel Castro's user avatar
-1 votes
1 answer
50 views

How to convert the equation into this two forms?

The equation is: x0^2/a^2 - y0^2/b^2 == 1 How to convert to this two forms: b^2 x0^2 - a^2 y0^2 -> a^2 b^2 and ...
csn899's user avatar
  • 3,707
1 vote
0 answers
86 views

Attempt to find a solution (out of potentially many) to a system of equations with FindInstance runs forever or crashes

I have a system of equations that in principle should have a solution (I would think not a unique one), which I want to solve. I am not interested in all solutions; I just want to locate one, assuming ...
AG1123's user avatar
  • 571
1 vote
0 answers
63 views

Computing Displacement Potential functions

I am new to Mathematica. I am trying to compute the displacement Potential functions. My code is as follows. ...
S. Pant's user avatar
  • 11
0 votes
2 answers
57 views

How to interpret the solution and how to work with it further?

Please help me understand the solution to the following problem: ...
Vladimir's user avatar
  • 161
1 vote
1 answer
82 views

Minimization of an implicitly specified function

exp - an experimental data, where expT - temperature, expChi - magnetic susceptibility I ...
Mam Mam's user avatar
  • 1,793
1 vote
1 answer
215 views

How to simplify? [closed]

The original formula is: Abs[(a b)/x0]/(2 Sqrt[1 + y0^2/x0^2]) How do you convert operations to get this result? ...
csn899's user avatar
  • 3,707
0 votes
1 answer
89 views

How can the process of hyperbola problems achieve the desired results?

As shown in the picture above, in the hyperbola x^2/a^2-y^2/b^2==1, point P is any point on the hyperbola, through the point P respectively do two asymptotes of the hyperbola parallel line PA, PB. The ...
csn899's user avatar
  • 3,707
0 votes
3 answers
106 views

Calculate Bernoulli numbers ( with a twist) [closed]

Mathematica has an inbuilt function BernoulliB that calculates $B_n$ for which, $$\frac{t} {\left(e^t-1\right)}=\sum_{n=0}^{\infty} \frac{B_n}{n !}t^n $$ I need to ...
Dotman's user avatar
  • 424
0 votes
1 answer
50 views

How do I plot a 2D function with an intermediate variable?

I have a function $c\cdot\frac{x^2}{x^2 + 10^{-6.367}*x + 10^{-6.367-10.32}} + x = c\cdot\frac{10^{-6.367-10.32}}{x^2 + 10^{-6.367}*x + 10^{-6.367-10.32}}+\frac{10^{-14}}{x}$, where $0 < x < 10^{...
HasturQ's user avatar
0 votes
1 answer
127 views

Kernel Crash Using Solve

The following code crashes the Kernel with no error message. ...
Just Some Old Man's user avatar
2 votes
1 answer
51 views

A matrix given by some parameters and variables. How to determine those parameters so that the matrix is independent of all variables?

For example, I have a matrix A given by some parameters (a,b,c,d) and two variables (x,y), $$ A=\begin{pmatrix}a&a+bx\\(c-d)y&a(c+d)\end{pmatrix} $$ The condition is that A is a matrix ...
Curious Cat's user avatar
0 votes
0 answers
94 views

Solve does not find solutions to large equation rotation matrix

I've been seeing some posts already where people mention Solve needs a bit of help to get things solved in some scenarios. I have been trying to figure out the solutions for equations. For the XYZ ...
Jose's user avatar
  • 11
1 vote
1 answer
63 views

How to get the range of t value in a Manipulate for trajectories?

How would I find the final time for different v and theta values so that the range of t in the manipulation would change for different v and theta values? ...
taki's user avatar
  • 11
0 votes
1 answer
97 views

How to extract fixed factors after equation term shift?

The equation given is: y - y1 == (y1 - y2)/(1 - x2) (x - 1) How to transfer y1 to the right side of the equation and extract the common factor (y1 y2)/(1 x2) to ...
csn899's user avatar
  • 3,707
0 votes
0 answers
99 views

How to solve recurrence equation using RSolve?

How can I solve the following recurrence equation while I dont have the initial values? Is it possible to solve this using RSolve? ...
mehrosadat ebrahimi's user avatar
2 votes
1 answer
105 views

How to code retarded time in Lienard-Wiechert potential equations?

I have been making strides on my project with the help of others here but have run into another snag: I am having difficulty in expressing the Lienard-Wiechert potentials with retarded time. For ...
JDRobin's user avatar
  • 55
2 votes
2 answers
105 views

NDSolve of a non-linear ODE

I am trying to solve the following non-linear ODE numerically: ...
Zazu's user avatar
  • 23