New answers tagged

3 votes
Accepted

Extract boundary points of an interpolating function obtained by NDSolve

We can use "Domain" to extract the values. {rmin, rmax} = (h /. sol[[1]])["Domain"][[1]]; rmin rmax
cvgmt's user avatar
  • 63.3k
2 votes
Accepted

Plotting an integral with solving for a specific constant

As an example, we take a simple function that we can integrate analytically: f[t_] = t + 2; Integrate analytically: ...
Roman's user avatar
  • 45.9k
5 votes
Accepted

Strange behavior of GroebnerBasis

Obviously MMA consider n as a variable. You can see this by writing: GroebnerBasis[1/(n (n - 1)) + x, {x, n}] what is the same as your result. To circumvent this, ...
Daniel Huber's user avatar
  • 47.1k
0 votes

How to modify the order of symbols to make the result more logical

The warning by @Bill in a comment about *Form functions is well made. The following works, but it appears that PolymonialForm ...
user1066's user avatar
  • 15.5k
1 vote

Solution of a sixth degree polynomial

It is advantageous to solve the expression for x first and introduce new parameters a -> \[Alpha] M, r -> \[Rho] M: ...
Ulrich Neumann's user avatar
2 votes

How to modify the order of symbols to make the result more logical

The function "rearrange" The function rearrange[expr,listOfFinalPositions] rewrites a sum in the order prescribed by the list entitled "...
Alexei Boulbitch's user avatar
0 votes

FindRoot with input as a list

Your equations are simple enough that you can use Solve: Solve[{eq1==0, eq2==0, eq3==0}, {a, b, d}] {{a -> -60, b -> (k (...
Carl Woll's user avatar
  • 130k
1 vote

FindRoot with input as a list

...
Bob Hanlon's user avatar
  • 151k
1 vote

Solution of a sixth degree polynomial

Evaluating M and a, this can be done as follows. ...
user64494's user avatar
  • 24k
2 votes

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?

No need to use FindInstance. In fact you can generate all possible equations with prescribed roots r1 and ...
azerbajdzan's user avatar
  • 9,653
2 votes

Adding Points on an Elliptic Curve

You can code this as follows (for distinct p1,p2): ...
ubpdqn's user avatar
  • 58.7k
3 votes
Accepted

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

FWIW this can be solved by brute force: e.g. b = Tuples[{0, 1}, 3]; t = Tuples[{0, 1}, 8]; sol[s_] := Select[t, Mod[# . b, 2] == s &] Solutions can be ...
4 votes

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

An equivalent version to user64494's answer is the following: ...
Carl Woll's user avatar
  • 130k
3 votes

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

This can be done as follows. ...
user64494's user avatar
  • 24k
1 vote

Multiple solutions from NSolve

With the OP's sol, we can gather the similar solutions together, find their mean, and if desired, polish them up with FindRoot: <...
Goofy's user avatar
  • 773
4 votes
Accepted

How to solve this integral equation numerically?

Although the general problem in the question probably requires the methods referenced by flinty in 285076, the specific problem contained in the question's code, ...
bbgodfrey's user avatar
  • 60.7k
5 votes
Accepted

Numerical solving diffusion equation in spherical coordinates

Change your boundary conditions to DirichletConditions ...
Ulrich Neumann's user avatar
1 vote

First order differential equation with two conditions

To long for a comment! You might check your expected solutions directly. Examplary for the first one ...
Ulrich Neumann's user avatar
0 votes
Accepted

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

Your claim "the programm [program] do [does] not start the Solve function process" is not true: the returned inputs mean the Solve cannot solve those and ...
user64494's user avatar
  • 24k
0 votes

Solving A System of Two Implicit Equations

An alternative approach is to use FindRoot or FindMinimum without constructing an ...
bbgodfrey's user avatar
  • 60.7k
3 votes
Accepted

Selecting Solve results according to conditions

You can add those conditions in Solve, but you also need to specify eg that $a>0$: ...
MarcoB's user avatar
  • 65.8k
4 votes

Selecting Solve results according to conditions

There could be shorter way. How about f[x_, y_] := L x y; g[x_, y_] := x^2 + y^2 - a; res = SolveValues[D[f[x, y] + λ g[x, y], {{x, y, λ}}] == 0, {x, y}, λ] and ...
Nasser's user avatar
  • 137k
4 votes
Accepted

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?

...
Roman's user avatar
  • 45.9k
4 votes
Accepted

Solving A System of Two Implicit Equations

First plot the function you want tointerpolate ...
Ulrich Neumann's user avatar
0 votes

Can a redundant condition be removed from a solution?

Simply remove Reals from your code if you do not want the condition. Solve[{(p-x)^2 + (q-y)^2==d, p/q==t}, {p,q}] $$\left\{\...
azerbajdzan's user avatar
  • 9,653
1 vote
Accepted

Can a redundant condition be removed from a solution?

The simplest way, no pun intended, to remove your condition, tell Simplify it is true. ...
Bill's user avatar
  • 11.7k
0 votes
Accepted

How can i create an equation with a sum?

Have you checked on-line help? Anyway, I would make a list of the variables, and use that. Something like: ...
Jyrki Lahtonen's user avatar
3 votes

`Reduce` is running forever

Making use of quantifiers, the following can be done. ...
user64494's user avatar
  • 24k
2 votes

`Reduce` is running forever

Designate the sixteen inequalities given in the question as ineq. The corresponding variables are ...
bbgodfrey's user avatar
  • 60.7k
4 votes
Accepted

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

...
Bob Hanlon's user avatar
  • 151k
3 votes

Multiple solutions from NSolve

For parametric research it could be better to use FindRoot as follows ...
Alex Trounev's user avatar
  • 41.8k
1 vote

Multiple solutions from NSolve

Setting WorkingPrecision->20, it then takes 85 sec. and gives only 3 solutions, although it gives a warning that the input is less precise than working precision: ...
Daniel Huber's user avatar
  • 47.1k
8 votes

Cannot solve this polynomial equation

...
Bob Hanlon's user avatar
  • 151k
4 votes
Accepted

Newton Raphson apply to Van der Waal Equation

To find curve we can use this code ...
Alex Trounev's user avatar
  • 41.8k
0 votes

Solving a non-algebraic equation at the symbolic level

As @Artes guessed, Mathematica 13.3.1 on Windows 10 can demonstrate both solutions are equal. For example, ...
user64494's user avatar
  • 24k
1 vote
Accepted

Find an instance satisfying equation

It seems there is no real solution in view of ...
user64494's user avatar
  • 24k
2 votes

Solving Nonlinear Algebraic Equation

It solves it fast if you use Reals. Also you really should use Exact input with Solve ...
Nasser's user avatar
  • 137k
1 vote

Solving inequality with `Reduce` doesn't work

The following works in 13.3.1 on Windows 10. ...
user64494's user avatar
  • 24k
1 vote
Accepted

Newton-Raphson Method Errors

The built in function FindRoot can solve your equations. I believe it uses Newton's method by default, though you can choose other options. For your equations, I found singularities were occurring ...
jdp's user avatar
  • 1,036
5 votes

Real zeros of complex function

Your function $\xi(k,B)$ does not depend on $B$ directly but only on $\cos(B)$, in a simple way. You can solve $\xi=0$ for $\cos(B)$ and thus find $\cos(B)$ as a function of $k$. ...
Roman's user avatar
  • 45.9k
3 votes

Real zeros of complex function

Try ...
Ulrich Neumann's user avatar
0 votes

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

A really simple way to get less solutions is to make your constraints tighter. Here I change the first constraint to be 10<=x[1]<=10 instead of ...
ydd's user avatar
  • 3,453
0 votes
Accepted

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

One of the ways is as follows. ...
user64494's user avatar
  • 24k
2 votes

How to solve this integro-differential equation in Mathematica?

Your equation is separable and can be solved analitically. If you define $$c(x,t)=c_1(x)c_2(t)$$ and substitute back into your equation, you see you obtain the two equations: $$c_2^\prime(t)=L\,c_2(t)$...
mattiav27's user avatar
  • 6,557
1 vote

How to solve this integro-differential equation in Mathematica?

Mathematica can't solve your integral equation, DSolve only returns a simplified form I think: ...
Ulrich Neumann's user avatar
2 votes

Solve[] isn't producing a correct result

To long for a comment NSolve evaluates all zeros for given parameter parameters (from @Larson's GeoGebra picture ) ...
Ulrich Neumann's user avatar
1 vote

Is there a way to divide associations by key?

a = <|A -> 2.02015, B -> 1.98025|>; b = <|B -> 0.538000, A -> 0.462000|>; In the above case it's simply ...
eldo's user avatar
  • 47.6k
4 votes

Solving system of first order PDEs

Update: Solution accuracy modestly improved and accuracy estimate appended. The Finite Element Method used in the last section of the question approximates the PDEs by thousands of sparsely coupled ...
bbgodfrey's user avatar
  • 60.7k
4 votes

Finding poles of a function

Since V 13.0 we have FunctionPoles:" From the documentation: "FunctionPoles returns a list of pairs {pole, multiplicity}." ...
eldo's user avatar
  • 47.6k

Top 50 recent answers are included