Questions tagged [equation-solving]

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

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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 ?
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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.
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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 ...
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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 ...
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1answer
50 views

Assumtion on Solve and DSolve

How to fix this problem I can't get something from this!! ...
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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?
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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: ...
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1answer
125 views

Solving equations with symbolic variables

I have the equations ...
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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 $...
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1answer
83 views

Non- linear ODE

I was working on this equation but I can't get out something for this: ...
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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 ...
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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: "...
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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 ...
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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 ...
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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? ...
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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 ...
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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. ...
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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: ...
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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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 ...
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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 : ...
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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 ...
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0answers
109 views

A Simple equation [closed]

I don't know why is not working?!! ...
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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 <...
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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? ...
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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: $p_1=A_2t^2+A_1t+A_0$ $p_2=B_2t^2+B_1t+B_0$...
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125 views

Could all eigenvalues of this matrix be positive?

I have the following list $\beta$ with 5 equations ...
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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)...
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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 $p$...
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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 ...
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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 ...
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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) == ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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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 ...
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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 $9.8598$ ...
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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? ...
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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 ...
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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 ...
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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 ...
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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 ...
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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: ...
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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, $s_1, s_2 > 0$. ...

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