312 views

### How to Collect $x$ powers to group $\sqrt{x}$ and $\sqrt{1+x}$ together?

I have been failing to apply Collect[#, x]& to render a like-power series of $x^k$. Here $k = \frac52, \frac32, \frac12,\frac{-1}2$, etc. The major issue is: ...
310 views

### Writing a trigonometric expression in terms of another [duplicate]

This is related to another question, in which one wants to rewrite a function of a single variable in terms of another function of that variable. Here I have a function of multiple variables. I want ...
200 views

### Substituting variables inside a matrix

I'm trying to substitute some dependent variables into equations inside of a matrix, however $Replace[]$ and and $/.$ don't seem to work. The equation in question is just a vector matrix of ...
153 views

### How to simplify an expression by substitution?

Sometime Solve and DSolve give a finial form of the solution, which is fine in may applications. However, in some cases, one may ...
153 views

### Substitution in expressions

As the title suggests, I want in an expression to to some substitutions. For example in the expression $\mathcal{L}^+_0+\mathcal{L}^-_0+\mathcal{L}^+_0+\mathcal{L}^-_0+\mathcal{L}_1$ I want to ...
229 views

### How to simplify expressions

I read several similar posts but I have not found a solution yet. However, I think that my problem should be quite easy. So here we are. Relations ...
132 views

### Replacing patterns (determinants) in a rational multivariate function and/or getting replacementFunction to work on a multi-linear expression

Given a rational multivariate function known to contain determinants, what is the best way to rewrite the function in terms of the determinants? A simple example: ...
95 views

### Treat 2 variable as 1

Is there anyway to treat two variable, that are a result of expansion, as one? To use Solve[] I can do ...
81 views

### Applying a simple transformation rule when Plus automatically simplifies

I have the following simple rules: {x2-x1->s1, -(x2-x1)->-s1, x3-x2->s2, -(x3-x2)->-s2} I want to apply that rule to the following: ...
141 views

### How to Pattern Match complicated patterns? [closed]

How can I get the output expressed in terms of p1 and p2 instead of exponentials? ...
94 views

### How does PacletInstall work? And is it possible to find packages using PacletInstall?

It seems that many packages published could be installed using PacletInstall . For example, from this Rubi install instruction webpage, we could see the comman: ...
50 views

### Replace subexpression that appears as inverse too

I have eq=Sqrt[(g m)/h] Tanh[Sqrt[h/(g m)] t] then I am trying to replace Sqrt[m g/h] by a symbol ...
63 views

### Assign a variable to an expression in Mathematica

I have the following matrix {{a^2 + b + \[Sqrt](m + n) + 5, 23 x + 7 a}, {14 b, a^2 + b + \[Sqrt](m - n) + 5}} I want to replace the expressions ...