# Questions tagged [syntax]

Questions on correct (or improved) formulation of Mathematica code to achieve particular results. Use this tag (not "symbol") for questions about all those odd @@ /@ # & and ~ characters.

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74 views

### Limit solution domain in Solve

How should you write the Solve command or another to give me solutions to this equation for example integers rationals Here are the equations: ...
155 views

### Why does OperatorApplied by default reverse the arguments?

Perhaps this is just one of those Mathematica curiosities, but I'd like to know why by default OperatorApplied[f][x][y] === f[y,x] versus the more usual way one ...
159 views

### Is it possible to pipe(afterthought apply function) with options?

For example, I have the following ...
50 views

### Define derivative as a new function

I’m coding my first physics simulation in Mathematica, and have a problem. I want to do the following inside a single cell input. ...
34k views

### How do I identify the source of a “Tag times protected” error?

I have some code that looks like Table[ a = 1; b = {2, 3} c = i;, {i, 2} ] which gives an error: Set::write: Tag Times in c {2,3} is Protected....
95 views

### Interpreting an ODE solution from DSolve

I'm doing a project where I need to solve an ODE. . I tried using DSolve to solve it, and it gave me an answer, but I'm unsure how to interpret it. The code I'm ...
47 views

### Correct syntax for tensor operators?

So I have an operator $A_0$ whose matrix representation is given by $$A_0 = \begin{pmatrix} 0 & -i \\ -i & 0\end{pmatrix},$$ and I also have two vector states $|0\rangle$ and $|1\rangle$ ...
37 views

### Issue with Compile for Complex Input/Output

I'm writing a Runge-Kutta algorithm for solving a system of coupled differential equations. My code works fine when defined as a module, but when I try to compile it, I get the following error: ...
72 views

### Isn't there a better way to display mathematical equations as labels, in Manipulate[ ] etc.?

I often want to output a mathematical equation in a text environment, and I find it very cumbersome and often the result is also not satisfactory. This example out of the "Advanced Manipulate ...
299 views

### Why does 'Transpose[list]' work but 'Map[Transpose[#]&, list]' not when attempting to transpose a 2D-array list? [closed]

I define this list: list={{100,100},{200,200}} Taking the transpose like this works as intended: Transpose[list] Taking ...
46 views

### How do I set a control in an “If” statement?

I have the following lines of code: ...
655 views

### Is there a linter to help write good Mathematica code?

I don't do much real programming, but I've recently been turned on to Atom, which has linter plugins for over 50 languages to make coding easier (most drawing on pre-existing lint-like programs). In ...
52 views

71 views

### Solving an equation for a power of unknown variable

How do I solve an equation for a power of $t$, e.g. solving $$-t(x–8)/8 = –2(x+4)/t$$ for $t^2$ instead of $t$, i.e. to get the answer $$t^2=16(x+4)/(x–8)$$ from ...
37 views

### Extract solutions in an interval for a trigonometric equation

Consider the solution x1 = x /. Solve[{Cos[x] + Sin[x] == 0}, x] The output is a conditional expression or, with //Normal, a ...
36 views

### What does <<2>> mean in an output? Double Less than or greater than signs [closed]

An error in my output gives I am trying to understand what the issue is. I was wondering if this <<2>> has anything to do with it, because I don't know what that syntax means. Is <<2>> ...
85 views

### Map substitution of variable in expression

If I have an expression involving a variable x, like 2x+1, and I have a list of different possible ...
25 views

### Clear assigned y'[x] from memory [duplicate]

If I, by mistake, write Mathematica assigns $y'(x)=y(x)/5$ and I don't know how to clear that from memory (I had to restart Mathematica). ...
107 views

### Plot a graph with an uncertain number of tangents

The code below tries to illustrate a graph ($y=(2-x^3)/x$) that can have 1-3 tangents depending on the tangent point $a$. ...
59 views

### Unable to find the exact dimension of an expression

I have defined a variable called y, this contains a huge equation, but when I look for the dimension of y it shows 3. How come a single expression has dimensions of 3? It is supposed to be 1 right? <...
30 views

### TagSet::sym Error using Subscript [duplicate]

I am a beginner to Mathematica and I am trying to get it to solve some equations of a function (vector) $B$ of three components, but first I want it to know that the derivates with respect to one ...
2k views

### Incompatible Changes since Mathematica Version 7?

There is documentation of the incompatible changes made to Mathematica with each major release: Incompatible Changes since Mathematica Version 1 Unfortunately that documentation simply stopped ...
125 views