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

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2
votes
1answer
128 views
2
votes
2answers
117 views

Series expression of a Root object

I was wondering if it is possible to get Mathematica to return a series approximation of a Root object. Example: I want a series representation of x in terms of ...
1
vote
1answer
92 views
3
votes
2answers
144 views

Numerical root-finding: Find leftmost root in a domain

This is surely a duplicate, but I cannot seem to find a similar question. I use NDSolve to find an InterpolatingFunction y[t] ...
0
votes
1answer
171 views

Solving Integro-Differential equations

I need help solving this equation. Is there a built in function that solves this type of equations? DSolve wouldn't work. Updated equation: ...
1
vote
2answers
129 views

Solving matrix equation

How can I solve the forward equation S[t]=C+A*S[t+1]*(Inverse((I-B*S(t+1)))*A for t=1 to t=10 and ...
0
votes
2answers
182 views

Why does Solve give a wrong solution to an equation? [closed]

I have got a following equation: -(c - x)/Sqrt[b^2 + (c - x)^2] + x/Sqrt[a^2 + x^2] == 0. Trying to solve it for x, so I evaluate ...
3
votes
2answers
132 views

Finding solutions at non-differentiable points of a numerical function

Let's consider a 2D function we can evaluate numerically, but which is opaque to symbolic manipulation (this is just an example): ...
0
votes
1answer
60 views

Problem in evaluation of a solution and plotting

I've written out a code which solves a equation and uses this solution to find "ph". ...
2
votes
1answer
218 views
2
votes
1answer
106 views

Find tangency of InterpolatingFunction and circle

I am trying to use a system of equations to solve for the common tangent of a (polar) InterpolatingFunction and a circle. Unfortunately, both NSolve and FindRoot don't yield results, even when I ...
14
votes
3answers
1k views

NSolve gives additional solutions that don't satisfy the equations!

I am trying to solve the following polynomial equations in Mathematica: ...
0
votes
1answer
100 views

RSolve works slow and does not give an analytical solution for solving high order linear difference equations

RSolve@@{{a[n]-a[n-10]==101}~Join~Table[a[i+1]==101+10i,{i,0,9}],a[n],n} I want to get the exact form of general formulas, but ...
0
votes
1answer
228 views

How to solve a large system of non-linear equations

I would like to solve Saha equations on Fe, which have 27 unknowns. Saha equations basically give you the ratios of the unknowns, but the unknowns are subject to constraints. What function shall I ...
1
vote
2answers
78 views

Finding roots of a function with a varying parameter

So I'm brand new to Mathematica, and basically what I want to do is find the roots of a function at varying time intervals. The function I'm using is: ...
-1
votes
1answer
85 views

Define a function and then integrate and plotting of the solved function [closed]

First I want to solve for $n_{0}$ for a fixed value of $n$, lets say $n=1$ $$ n= n_{0}+ \dfrac{1}{2}\int_{-1/2}^{1/2}dq\left(\dfrac{e_{q}+Un_{0}}{\hbar\omega}-1\right) $$ where $e_{q}=2[1-cos(2\pi ...
-1
votes
1answer
81 views

How to assign variables to selected roots of a polynomial equation? [closed]

I have a polynomial equation like the below, and I want to assign variables to the roots that are not pure imaginary. How I can do this? ...
1
vote
1answer
71 views
1
vote
1answer
218 views

Solve a system of parametric equations

I have a system of parametric equations (with a total number of 8). I tried to solve this system by using Solve. I have not received an answer after about 4 hours! ...
0
votes
1answer
57 views

Is there a way to have FindInstance or Solve give only positive integer solutions?

I keep getting either negative or super long answers or super long negative answers in no particular order :\ ... Is there a way to only ask for positive solutions? (here we want 0 < x<(10^12+y) ...
0
votes
1answer
199 views
0
votes
1answer
87 views

How to create a line due to requiriements?

Considering we have three lines, and know the intersection points (How to find intersection points of lines?) How can I draw a line that will cross the intersection point of the two lines and will be ...
1
vote
0answers
104 views

How to find Pauli matrices

I wanted to find the Pauli matrices, so i wrote down this code: z = {{a, b}, {c, d}} i = {{1, 0}, {0, 1}} Solve[z.z == i, {a, b, c, d}] and mathematica gave me ...
1
vote
3answers
1k views

How to find intersection points of lines?

Considering I have three functions f1 = -x + 1; f2 = x - 1; f3 = x + 3; How can I find the intersection points of this functions? Thanks. This didn't work ...
2
votes
1answer
133 views

Optimizing alphametrics code

First of all, thank you all in this great community. I have been reading a lot of threads about Mathematica optimization learning things like using Compile ...
1
vote
0answers
402 views

Solving Symbolically Equations with Vectors and Matrices

I want to solve equations with vector variables and vector/matrix parameters symbolically. As a basic example I would like to be able to solve something like $[I-aG]x=b$ where $a,b \in \mathbb{R}^l$ ...
0
votes
1answer
84 views

How to extract a solution

Is there any way to get the actual number from this? NSolve[x^2 - 5 y^2 == 1, {x, y}, Integers][[1]][[1]] instead of ...
1
vote
0answers
101 views
12
votes
2answers
15k views

Figuring when the minute and hour hand coincide on a clock

I would like to list all possible times in a 12-hour period, where the hour hand overlaps the minute hand completely. This is really a question about three distinct things - to be done in Mathematica ...
-1
votes
1answer
109 views

How to get a 3D plot of from the the solutions of function [closed]

I have the following equation: (1 - x)^2 + T^2/((f[x] - L)*(f[x] - L - 2*T))*(P/(N-R+S)) == 0 f[x] = (x*r*(T + L) - T)/((x*r) - 1) ...
0
votes
1answer
104 views

How to put a condition in 3d plotting

I have the following plotting question: First I want to have 3D plot of Alpha respect to different values of p and l when we ...
0
votes
1answer
125 views

Plotting results of a NSolve problem

I am calculating, numerically, the zeros of a determinant. a1 and a2 are constants, q is a parameter. I would like to vary q and find the roots w as a function of q and plot roots w vs. q. All ...
1
vote
1answer
178 views

NSolve on bounded domain

I don't expect NSolve[] to be able to obtain all solutions in generalfor example. In principle there should be an algorithm that finds all solution to $f(x)=0$ for ...
0
votes
1answer
152 views

Plotting an extremly large output

I'm trying to plot the solutions of this determinant: ...
11
votes
3answers
431 views

FindInstance with a Diophantine equation seems to go on forever

I tried to find a non-trivial integer solution to the equation $$2012^2=a^2+b^2+c^2+d^2+e^2$$ with Mathematica but the computation takes minutes; I might be doing something wrong. ...
3
votes
3answers
424 views

How to solve the equation $A \sin x + B \cos x = 0$ for all $x$?

I have the equation: $A \sin x + B \cos[x] = 0$ that should be satisfied for all the $x$. Of course, the solution is obvious: $A=B=0$, but I need Mathematica to resolve it automatically because this ...
1
vote
1answer
227 views

NSolve fails to solve a nonlinear equation

Mathematica can not solve this: g = 9.82; ω = 0.5; h = 5; y0 = 1; v = 0; τ = 0; NSolve[h + v t - (g t^2)/2 == y0 Sin[ω t], t]; The error code is: ...
2
votes
2answers
161 views

How do I get all the roots within a certain range for an equation? [duplicate]

I wish to find ALL the roots of the following equation $ x \tan(ax) - c = 0$ within a range, where a and c are constants I control. I've been using ...
0
votes
1answer
85 views

How to solve this equation? or get the numbers of solutions of the function?

I have a function like this.. $$ f[k]=\int_0^\infty Exp[-ax]x(Cos[bx])^{2}BesslJ[0,kx]dx $$ I want to know how many local maximuns this function has.. So I try to get the derivative of f[k] $$ ...
1
vote
1answer
80 views

How to solve these equations by Mathematica?

l tried it with Solve,DSolve and NDSolve functions,but all failed.Should l simplify the equations in the papers or use other mathematica functions.Thanks~
1
vote
2answers
79 views

Solutions to multivariate equation

Is there any way to get Mathematica to give a set of solutions (pairs of x and y that are integers) to an equation with multiple variables? Something like: ...
0
votes
0answers
179 views

Solving a system of equations involving partial derivatives for a wave

Before saying anything about the problem, I have checked "How to solve a system of partial differential equations?" yet it does not actually answers my question, as I have a 10x10 matrix to work on. ...
1
vote
0answers
81 views

Equation solving: Solve returns a periodic solution

I have a very simple trigonometric equation, that I've been trying to solve for a variable for a few hours now: (I couldn't find how to correctly format this) ...
0
votes
1answer
104 views

Why does this work with Wolfram|Alpha but not Mathematica? [closed]

I ran into this while doing some work today: It's the exact same syntax - and I expected that Mathematica would be more likely to be able to solve it, since oftentimes Wolfram|Alpha doesn't have ...
0
votes
0answers
44 views

Initial values/parameters in equation system of dimension 32

This is a system of equations of dimension 32, that describes an economic system. I want to find a set of parameters and initial values in which the system can be solved, and solve the system of ...