Questions tagged [equation-solving]
Questions on the analytic and numerical equation solving functions of Mathematica (Solve, Reduce, NSolve, FindRoot, DSolve, RSolve, etc.).
5,456
questions
0
votes
0answers
39 views
2 equations 2 Unkowns at loop variable input
I want to solve a system of equations
2 equations 2 Unknowns at loop variable input at the equations
how could I do that ?
1
vote
2answers
80 views
LinearSolve with 4 variables and 3 equations
Is it possible to find a solution or at least run LinearSolve when there are 4 variables and 3 equations.
For example:
a + b -3c + 4d = 4;
2a + 5b -6c +2d = 15;
3a -4b + 5c -3d = 10.
0
votes
0answers
32 views
Unbounded solution at boundaries with few combination of values in this BVP solution
I had asked a question here regarding solution to a BVP problem. bbgodfrey provided an excellent answer using the method of integrated least squares.
However, for a few specific set of values of ...
0
votes
2answers
68 views
A problem when solving an equation with symbolic variables
I asked a question a couple days ago and received a solution that worked for me at the time. But now I am seeing that the proposed solution fails for some other cases I need.
For example, if I just ...
0
votes
1answer
50 views
0
votes
1answer
38 views
Using the symbol of the system of equations [duplicate]
Part 1
I'd like to know how to use the symbol of system of equations (left curly braces). I tried the following code:
Part 2
How can I add a third equation?
0
votes
1answer
84 views
Symbol of system of equations
I'm wondering if there is a way to use the symbol (the left curly bracket) of a system of equations. So far I found only the following "symbol":
I need to remove the two conditions.
EDIT2: ...
2
votes
1answer
125 views
2
votes
1answer
59 views
How to find constrains on variables that make a system of inequalities not have a solution
My problem is as follows:
How do I ask Mathematica the following question. Let $f(x,y,z,a,b)$ be a 5 variable polynomial. I want to find all values of $a,b$ for which $f$ has no zeros in the region $...
1
vote
1answer
83 views
0
votes
1answer
52 views
How to obtain exact answers for casus irreducibilis for third order equation in Mathematica
According to https://en.wikipedia.org/wiki/Cubic_equation#General_cubic_formula
When a cubic equation with real coefficients has three real roots, the formulas expressing these roots in terms of ...
5
votes
1answer
165 views
Using FindRoot[] to find an inflection point
FindRoot[
{Derivative[2][SinIntegral[x]], 0 < x < (Pi)},
x
]
I hoped that my code would return a value for x=0 but it is returning an error:
"...
0
votes
0answers
65 views
How to avoid imaginary numbers as solutions from Sqrt?
test function is the answer that I get from calculating the eigenvalues of a matrix. I need to calculate the square root of it. After I substitute the values for qx and qy, I am expanding it with ...
0
votes
2answers
120 views
How do I know Mathematica is doing exact algebra?
I am looking for zeroes of the following polynomial:
-36 - 20 a1 a2 + 16 a2 b1 + a2^2 b1^2 + 16 a1 b2 - 20 b1 b2 - 2 a1 a2 b1 b2 + a1^2 b2^2
in the region
...
2
votes
2answers
169 views
Is it possible to find a non-zero solution of an ODE?
Is it possible to solve the 4th-order ode analytically?
...
1
vote
1answer
38 views
Reduce relations with Fibonacci function never terminates,
i have a reduce operation which includes Fibonacci function. but the problem is it never terminates, i tried some modifications, for example removing f1 in my relation. sometimes it works and at least ...
0
votes
1answer
56 views
ODE solution for a simple case
I was trying to solve this but I can't not fix the problem :( please help me.
a,b,f and d positive vale.
...
0
votes
0answers
24 views
neither a list of replacement rules nor a valid dispatch table, and \ so cannot be used for replacing [closed]
I have following problem. I would like to Evaluate simple equation:
...
4
votes
3answers
151 views
Challenges and Opportunities of `FindInstance` Command
I'm testing the FindInstance capabilities and ran into one problem that behaves similarly with different types of inequalities. I calculate two points satisfying ...
1
vote
1answer
153 views
Show solutions of non-linear equations with multiple variables in 3D space
Consider a (non-linear) system of equations with two parameters x and y and multiple variables ...
1
vote
2answers
88 views
Is task to find intersections of a line and a cubic Bezier curve really so hard?
I wrote formulas for parametric Bezier curves of different orders
...
0
votes
0answers
44 views
Equal equations or Expressions
I would like to check if equation (Sigmaa22) is the same as equation (stress)
Basically i have 2 equations one is called Sigmaa 22 and the other one is called stress,My problem when i try to check if ...
1
vote
1answer
79 views
How can I derive all the roots of a complex equation containing the square root of Sinh^2 using Mathematica [closed]
I have the following equation:
where m,n are arbitrary natural numbers and beta and k are positive nonzero real numbers.
How can I find all the roots of this equation using Mathematica?
1
vote
2answers
107 views
Mathematica: How can I solve the problem "The Kernel Local has quit (exited) during the course of an evaluation"
I am using a Mac Book with Monterey and 16GB RAM for a calculation with 2 nested For loops.
I am relatively new to Mathematika and still trying to learn the language properly, so I hope the problem is ...
0
votes
0answers
79 views
Solving a linear system with large number of equations
I am trying to solve a system of linear equations having 16 equations and 16 variables. These 16 equations are as below :
eqn1 :
...
3
votes
0answers
83 views
Solving or Minimizing the Norm of the matrix equation $M^TAM - M^TB - B^TM =C$
I am trying to solve the matrix equation $M^TAM - M^TB - B^TM=C$ where I know A, B and C. My unknown matrix is M which has the special form that all the rows and columns sum to zero.
i.e. I have four ...
1
vote
0answers
109 views
0
votes
1answer
46 views
rewriting the solutions of symbolic 3rd and 4th order polynomials
I have symbolic third and fourth-order polynomials which read.
$F_{3}= x^3+p x +q,$
$F_{4}= x^4+p_{0} x^2 +q_{0} x + r_{0}.$
Using the Mathematica, I can find the roots of these polynomials using
<...
0
votes
0answers
64 views
Is this set of equations solvable?
I am trying to solve a set of equations. I ran it for several days but it's still running. Is this solvable?
...
0
votes
1answer
60 views
Formalization of one optimization problem or solution of inequalities - Part №2
Continuing the question: Formalization of one optimization problem or solution of inequalities
Let's consider a more complex problem. We have two polynomial:
$p_1=A_2t^2+A_1t+A_0$
$p_2=B_2t^2+B_1t+B_0$...
0
votes
0answers
125 views
Could all eigenvalues of this matrix be positive?
I have the following list $\beta$ with 5 equations
...
4
votes
2answers
236 views
Using NDSolveValue for Solving a parabolic PDE numerically
Inspired by this question I am trying to solve the following PDE numerically on $x \in [-3, 3]$ and $t \in [0, 0.5]$ using NDSolveValue:
$$
\frac{\partial p}{\partial t} = (12x^2-4) p + \left[4x(x^2-1)...
2
votes
1answer
69 views
Formalization of one optimization problem or solution of inequalities
I have polynomial:
$p=A_2t^2+A_1t+A_0$
$A_0=(x^2-y^2)+xz$
$A_1=x^2+y^2+z^2+\sin(x)$
$A_2=x^4+y^3+z^2$
$x,y,z$ - parameters, moreover $z$ - the value of which varies in the range $[0,1]$.
Polynomial $p$...
1
vote
0answers
91 views
RootSearch problem when called from within ParallelDo
I have been using Ted Ersek's RootSearch package for Wolfram Mathematica for many years. The package worked great, including inside the ...
2
votes
2answers
63 views
NSolve not solving within Table
I would like to solve an equation for different parameter values, thus, I used Table[] to create an array of solutions. For some parameter combinations {k,A} NSolve does not give an answer, but when I ...
-2
votes
1answer
77 views
some error without reason [closed]
I just start to work with this code but it is not running?!
Clear["Global`*"]
eqns = {y[x]^2 - ((1/52)*Sqrt[3]*y[x])Sqrt[y[x]^2 + (x)^-2/1000 - (69/100)] + ((49 (x)^-2)/100000) - (69/100) == ...
2
votes
2answers
86 views
Mathematica code for Newton's Method doesn't work [duplicate]
I am trying to program Newton's Method in Mathematica to compute the roots of $f(x)=x^3-6x^2+11x-6$ using the Do command but my code gives a ...
0
votes
0answers
35 views
Matrix with Gauss method in Mathematica [duplicate]
I need to define a matrix and write code to solve it with the Gaussian method. When I write the dimensions of the matrix, it should be calculated. Could you please help?
0
votes
1answer
73 views
How to solve matrix equation in Mathematica?
The following 8-dimensional matrices are equal,i.e., matA is equal to matB. How can I solve for the elements ...
5
votes
2answers
170 views
Efficient way of finding polynomial relation
I have a list p of polynomials of k, and a list of "parameters" x,y,z which are ...
0
votes
1answer
162 views
Solving Lagrangian with Mathematica [closed]
I'm pretty new to Mathmatica but I'm trying to use it to find a Lagrangian and then find the equation of motion from the Lagrangian.
Think the method is correct but I just cant seem to get the syntax ...
1
vote
1answer
155 views
Find right end-point satisfying an integral constraint
I am solving the following system of first-order ODEs with a variable right-end point l1num and boundary condition at that point ...
3
votes
1answer
56 views
Which one is more accurate Solve or NSolve? How can I get the same result as Solve using NSolve in the given code?
I am using this code to calculate the quantity $sol$. Using Solve, I get the result $9.8598$
...
1
vote
2answers
47 views
How to use solution of NSolve as a list and them plot?
I am solving a set of equations with one of the parameters Rload as a list. After I solve it, how do I calculate power of each Rload using the formula power=(X-Y)*Rload, and then plot power vs Rload?
...
1
vote
1answer
92 views
Solving system of simultaneous equations [duplicate]
I have a system of two equations to solve.
My input is
Solve[y*x - 1/x - 1/x^2 == 1 && z*x - 1/x^2 + 1/x == 2, {y, z}]
and output is
...
1
vote
1answer
41 views
How to solve system of equations in Do loop and replace the answer?
I want to solve equations and substitute one of the variable with the answer.
For example, here I have two variables (x, y) and two constants (a, b) ranging from 1~10, use FindRoot to solve them. I ...
0
votes
0answers
57 views
Exclude a term in a differential equation
How can I exclude this term (The red box) from derivation to make it consider it as a constant (Just a constant to be multiplied ), I am getting the differentiation for the whole equation but I want a ...
4
votes
1answer
127 views
Asymptotic Solve
I am trying to solve a set of equations in Mathematica.
My input is
Solve[y*x - 1/x - 1/x^2 == 1 && z*x - 1/x^2 + 1/x == 2, {y, z}]
and output is
...
1
vote
1answer
56 views
How can I solve the following equation for k?
I want to solve the following equation for k, where s1,s2,s3 are given constants:
...
0
votes
2answers
76 views
Min and Max of a function
I need to obtain for what $a_i$'s the function:
$$a_1 \ln (\sqrt{2\pi e} s_1) + a_2 \ln (\sqrt{2\pi e} s_2),$$
has a maximum and minimum, under the constraint $a_1 + a_2 = 1$; also, $s_1, s_2 > 0$.
...