# Tagged Questions

How to manipulate expressions structurally, not necessarily complying with the rules of algebra.

65 views

### How can I access a variable using Position?

I want to define a vector PosVec[a, b] dependent on the variables a and b of a matrix ...
30 views

79 views

### Deriving the Fourier Coefficients Formulas with a Manual Procedure

I already know that there are built-in functions to compute the Fourier coefficients but I want to derive their formulas manually. In fact, I want to obtain the final well-known formulas for the ...
2k views

### Replacement inside held expression

I wish to make a replacement inside a held expression: f[x_Real] := x^2; Hold[{2., 3.}] /. n_Real :> f[n] The desired output is ...
49 views

### Error: Recursion Depth of 1024 Exceeded During Evaluation

I wrote a function that exchanges integration and summation in an expression. ...
69 views

### Problems with Displaying Output for Summation

Consider the following code. ...
85 views

### Simplifying expressions

Let's define a function $\Omega(x,y)$ ...
66 views

### Replacing terms in a sum according to a condition

If I have a generic expression such as ...
68 views

### Creating Boolean expressions over a set of indexed variables

I've read lots of examples here on how to set one matrix Equal to another, but how do you nest And and ...
137 views

75 views

### Display position of expression as Tooltip

How could we display the position of any sub expression in an expression using Tooltip? This would be useful for example in order to locate the position of an ...