Questions on the analytic and numerical equation solving functions of Mathematica (Solve, Reduce, NSolve, FindRoot, DSolve, RSolve, etc.).
-1
votes
1answer
22 views
0
votes
1answer
34 views
How to solve the system of two equations to get the approximation value
I'm a Ph.D. student in Banking and Finance and I'm not familiar with the solving system of equations. I don't know how to solve the two equations below to get the approximation value of x, and y. All ...
2
votes
1answer
41 views
Unable to use `Solve` to solve simultaneous equations, or use `Maximize` for exact maximum solution
Mathematica has found that the maximum of the following function is negative using NMaximize, but I am trying to prove that the maximum is negative (i.e. that the ...
-1
votes
1answer
63 views
Solve or Reduce don't work with Integer functions
I had been trying to limit for some c++ programs, the bigest whole number they can handle is
lim = 18446744073709551615
and the different functions are:
...
1
vote
0answers
37 views
Why is my GroebnerBasis = 0 in this case?
I recently asked a question: Finding Intersections Between Arbitrary Surface and A Line whose solution required me to use the GroebnerBasis function. I successfully ...
0
votes
1answer
28 views
Not getting solution to simple equation [on hold]
qThis is my code.
R = 12.17
g = 9.8
θ = 36 Degree
Solve[R==v*cos[θ]*(v*sin[θ]+sqrt[(v*sin[θ])^\.1d2 \[Minus] 2*g]), v]`
What is the problem with this code?
1
vote
1answer
47 views
Solving a system of nonlinear equations with 8 variables
I want to solve this 10 nonlinear equations in 8 variables, expressing the variable as a function of one another. I have tried using Solve and Reduce, but couldn't get any result.
...
2
votes
1answer
47 views
Finding Intersections Between Arbitrary Surface and A Line
I have a self-intersecting surface H defined as follows:
...
0
votes
0answers
43 views
Solve not working
I'm trying to solve the following system of equations for ahat0, ahat1, ahat2 using the Solve function.
I know (algebraically) ...
0
votes
2answers
44 views
Finding series expansion of solution of algebraic equation
I have the following algebraic equation:
...
0
votes
1answer
39 views
How to automatically select solutions from a set of solutions given by Solve?
I have a function of trigonometric functions which must be equated to zero in order to obtain the appropriate results. This is done in the following fashion:
...
0
votes
0answers
26 views
Can't solve InfiniteLine example: not a quantified system of equations [on hold]
I'm trying to complete an example from https://reference.wolfram.com/language/ref/InfiniteLine.html
Find the intersection of InfiniteLine[{0,0},{1,1}] and InfiniteLine[{{0,1},{1,0}}]:
But when I ...
3
votes
2answers
149 views
How do I find a function to fit these criteria?
I want to find a smooth continuous function f[x] that satisfies the following for real values of x:
...
0
votes
0answers
63 views
6
votes
4answers
178 views
How to find the numbers $a$, $b$, $c$, $d$ so that the equation has four distinct integral solutions?
I want to find the numbers $a$, $b$, $c$, $d$ so that the equation
$$x^4 + a x^3 + b x^2 + c x + d=0,$$
where $d = \dfrac{c^2}{a^2}$
has four distinct integral solutions.
With Maple, I found some ...
0
votes
2answers
54 views
Finding a numerical solution and plotting it over a wide range
My problem is that I am trying to find a Numerical solution to a function of the form f(x,c)== K for x for some given values of c, K, and plot this function over a wide range of values of c.
My ...
0
votes
0answers
27 views
Solve/Simplify an Equation that involves multiple variables for one variable e.g. x
I am new at Mathematica and have very basic knowledge about it. I want to solve the following equation for variable x in Mathemtica.
...
0
votes
2answers
37 views
Calculate value of expressions based on solution of given linear equations
I have these three equations:
1/X + 1/Y == 1/15;
1/Y + 1/Z == 1/20;
1/Z + 1/X == 1/25;
I want to calculate the value of expression:
...
4
votes
3answers
91 views
0
votes
0answers
38 views
0
votes
3answers
79 views
How to solve this 4th degree polynomial equation with complex coefficients numerically in Mathematica?
I have a polynomial equation:
$-(a-ib)e^{(4\pi i/3)}(\sqrt{2}i+x^3/\sqrt{3})x- (a+ib) e^{(2\pi i/3)}(\sqrt{2}ix^3+1/\sqrt{3})=0$
(which in code is):
...
0
votes
1answer
109 views
Solve a Second-Order Differential Equation Numerically, with boundary conditions?
Below is an ODE with BC define as x[R]=0, x'[0]=0, x'[R]=0 and parameter n. The ODE is stiff at certain data, and I need to see the behavior of x' and x for given ...
1
vote
1answer
66 views
PDE in 3D: Specification boundary condition at infinity
I'm trying to solve the Schrodinger equation and having difficulties to define a
limitless region because the problem has the Dirichlet conditions at infinity. Maybe I don't need such a region and ...
0
votes
2answers
72 views
How to speed up this calculation regarding the normal distribution?
This calculation takes a very long time!
Why?
How can I improve it?
Thanks!
...
3
votes
2answers
297 views
Help needed to make NIntegrate Converge
I have the following notebook (trying to caclulate the pull-in voltage of a structure):
...
2
votes
2answers
175 views
Solving an equation with vector coefficients
I want to solve $(ct)^2 = d(t)\cdot d(t)$ for $t$, where $ d(t) = \frac{1}{2}at^2 + vt + r$
Where$ a, v$, and $r$ are all 3-dimensional vectors in Cartesian coordinates. How can I do this?
1
vote
1answer
47 views
3
votes
2answers
109 views
Schrödinger equation for a hydrogen atom and lack of memory
I'm trying to solve the Schrödinger equation for a hydrogen atom in the Cartesian coordinate system.
This is my code
...
5
votes
1answer
109 views
How to solve this equation numerically or analytically
In the paper, entitled:
A Closed Form Solution for the Pull-in Voltage of the Micro Bridge
(Link to PDF: https://pdfs.semanticscholar.org/0d31/33707b1243f6b4e3344c4fa19b831b010b8b.pdf)
... the ...
0
votes
0answers
25 views
Plotting numerical solution of the system when parameters change
I have a system of three equations in three unknowns, $k$, $w$, $\theta$.
I am interested in solving the system and finding how the variables behave when some parameters change, say $\beta$ and $\...
2
votes
2answers
101 views
Problem with NSolve Speed
I have a very complicated function but only of 1 variable. I want to find the first value for which that function is zero. Mathematica can easily plot it:
...
1
vote
1answer
35 views
Strange output for solve in terms of trigonometric functions
I am using the following Solve code:
...
1
vote
1answer
53 views
How to represent in a 3D graph the set of solutions to this system of inequalities?
I am studying this piecewise function:
...
0
votes
0answers
30 views
Getting solutions restricted to an interval [closed]
Suppose I want to solve something like:
Solve[Sin[2x] == 0]
but am only intrested in solutions between a < x < b
Is it ...
1
vote
2answers
27 views
Choosing among Conditional Expressions in Solve
I am solving the following symbolic equation. The parameters are of certain ranges, which I specify using Assuming. However the solution presents a list of values, ...
0
votes
1answer
45 views
Roots of an expression
I have an expression as
$1 - 2 \sqrt{1 + i r} + i r$,
where $r$ is real.
I want to find the roots of its imaginary part. So:
...
0
votes
1answer
26 views
Conditions on parameters in Reduce
i have a system of equations in which there are two parameters F, G. I choose F,G positive. the code is:
...
0
votes
1answer
62 views
Solving two nonlinear equations in two unknowns
This is my code defining two nonlinear equations. I want to solve them simultaneously.
...
0
votes
1answer
50 views
Estimating parameters for pair of differential equations efficiently
I'm trying to estimate the parameters for the following pair of differential equations
...
0
votes
0answers
54 views
Solve vs Reduce and use of parameters
i'm new in the world of mathematica. i have a simple problem : i want to find a solution of a system of equations. The problems are:
1) Is it better to use Solve or Reduce (for this kind of ...
0
votes
1answer
69 views
Solve won't return an answer for a set of four equations
So I was doing my homework and this system popped up, so I was trying to solve it but Mathematica has just been stuck with it for two days. It won't give me an answer.
I am trying to get the code to ...
0
votes
1answer
102 views
Huge time to plot a function with replace all (/.)
I am looking to plot the function f[x, y]
f[x_?NumericQ, y_?NumericQ] := Cos[x + y]/Sqrt[1 - y^2]
where ...
1
vote
1answer
20 views
Manipulate plot using solution from Solve [duplicate]
Hi I'm trying to visualize a 2D equation that I have previously solved as I vary a parameter 'b'. First I solve for 'y' in terms of 'x' and 'b', then I intend to use Manipulate.
...
3
votes
1answer
106 views
Newton's Method
Problem statement:
I'm currently new to Mathematica and have been trying to solve this problem. I was digging around and found this code:
...
0
votes
0answers
24 views
Why does reduce return the root of a pure function? [duplicate]
I want to find the zeros of some nonlinear function in a certain range, say $f(x)=x^4+\frac{x}{1-x}-c$. If I enter
...
3
votes
2answers
186 views
Solving a non-linear ODE system with ParametricNDSolveValue
I'm trying to solve a non linear ODE numerically with ParametricNDSolve, but as far as I got is shown below. My problem is to set the find root correctly.
What I ...
1
vote
1answer
75 views
How to get solutions for this system of inequalities?
I am new to Mathematica and I am struggling finding the solution for the following problem.
I am studying this piecewise function:
...
3
votes
0answers
47 views
Solve is not able to solve trivial system of equations [closed]
Mathematica can solve the following equation:
In[1] = Solve[{a == b + c}, c]
Out[1] = {{c -> a - b}}
But it does not solve the equation, if I add additional ...
0
votes
2answers
56 views
How to solve 16 coupled linear equation? [closed]
How one can solve 16 or more linear simultaneous equation in mathematica?
If there are 16 coupled linear equations with 16 variables, then how it is to be solved in mathematica?
1
vote
1answer
32 views
Using both subscripted and non-subscripted variables in an equation
I'm getting started with Mathematica, as I have been using Maple in the past. Is it possible to define two variables $\alpha_1, \alpha_2$ and then still use $\alpha$ as a parameter of a function and, ...
