# Tag Info

### I want to represent the function based on specific variables in Mathematica

You have to provide rules for substitution, e.g. Solve for relevant parameters and try to give them the form as they apear, as here in the last line going to $M^2$ ...
• 3,967

### Simplifying products of DiracDelta

Here's an extension of @Ulrich's solution, taking into account the Jacobian of the transformation: ...
• 239k

### Minimize the number of components in the output of Reduce

My problem was that the solutions provided by Reduce included both isolated points such as (x1==1 && x2==0 && x3==0), and open intervals whose closure was also part of the solution, ...
• 327

### Minimize the number of components in the output of Reduce

The following is like something I did once to have Mathematica set up and illustrate iterated integrals over regions in ${\Bbb R}^3$. It works on the example at hand, but it probably needs more ...
• 239k
Accepted

### Problem computing a limit

Sum[] is difficult to handle in general, and it seems to be why Limit[] is so slow. In this case, it's a polynomial and its ...
• 239k

### Problem computing a limit

The problems seems that for different $j$ you can get 1/0 division depending on what $x$ value is. So without having specific value of $j$ might not be possible. ...
• 147k
Accepted

### How to verify a FactorialPower identity?

Another way is to use FindSequenceFunction We start from FactorialPower[x - i*k, n, m*k] and compute a few values, say ...
• 16.4k

### How to verify a FactorialPower identity?

A very good indication is that it's true for $m=1\ldots30$ (and higher, if you have the patience): ...
• 48.8k

### How to simplify a pure function?

Using FullSimplifyFunction (by E. Chan-López, Carlos Francisco Arias Méndez & Ulrich Neumann): ...
• 27.9k

### Summation not returning a timely result

Another fast symbolic solution: ...
• 14.7k
Accepted

### Summation not returning a timely result

One problem is the combinatorial explosion of subexpressions to try to simplify in the straight sum. I love it when symmetry works: ...
• 239k

### Power of multiplication of powers

To address your question, let us look at the number of leaves in both expressions: ...
• 39.6k

### Power of multiplication of powers

For these types of things, it is better to use PowerExpand as it is designed for this. PowerExpand[((-1 + a^2)^2)^(1/4)] ...
• 147k
Accepted

### How to simplify the root of $\sqrt{-x^2-y^2-z^2}$?

ComplexExpand helps. ...
• 1,811

### How to simplify the root of $\sqrt{-x^2-y^2-z^2}$?

Adding to the possibilities: e = 1/Sqrt[-x^2 - y^2 - z^2]; Simplify[e, e^2 < 0]
• 4,572