# summation's questions - Danish 1answer

517 summation questions.

### 2 On Ж, and the fine-structure constant

0 answers, 17 views numerics summation numerical-value
I'm trying to reproduce the results from a certain infamous paper that has been moving around the web for the last few days. The details are irrelevant. This paper claims to have a closed-form ...

### What is wrong with my calculation ? [on hold]

0 answers, 36 views functions summation
Help ! I had a problem with Z[Tan] error Part miss part 5 or {{1,1,1,1}{1,1,1,1}{1,1,1,1}{1,1,1,1}} something like that so this my function

### -1 Please help me get the ratio of x to y [closed]

2 answers, 51 views equation-solving summation sequence
I need the ratio of x to y in this equation:sum [n*(x/10)^n/10^(n-2)] == y from n=1 to ∞Thank you!

### 3 Conditional Summations

4 answers, 168 views summation wolfram-alpha-queries
I am not a math major, but for a networking class, I am taking I am required to do summations for probability. I know the logic but I don't know the mathematical theory to make this work. Using ...

### 2 Plot variations in geometric sum within prescribed range

I have a simple geometric sum:Sum[a^(j + 1), {j, 1, k}]which evaluates to(a^2*(-1 + a^k))/(-1 + a)...

### 1 Find closed form for roots of trig formula

I have the expressionSum[(2 j \[Pi] Sin[(2 j \[Pi] x)/(r + 1)])/(r + 1)^2, {j, 0, r}] == 0I want to find the roots in terms of ...

### 4 Cumulative total of columns in a matrix or table

2 answers, 101 views list-manipulation matrix table summation
I have the following:matrix1 = {{a, b, c, d}, {e, f, g, h}, {i, j, k, l}, {m, n, o, p}}(Note that it's the data that matters, not the fact it's defined as a ...

### 1 Summing results of a table

1 answers, 36 views list-manipulation table summation
I have a simple table:example1 = Table[N[x^(x/r), 5], {r, 1, 10}, {x, 1, 10}]I want to create a new table ...

### 2 How can I get the simplest result of this sum?

2 answers, 56 views summation
I am trying to find the sum $$\sum _{k=1}^n \frac{k+1}{(k-1)!+k!+(k+1)! }.$$ I triedSimplify[Sum[(k + 1)/(( k - 1)! + k! + (k + 1)!), {k, 1, n}]]and got ...

### 1 Sum over multiindex

0 answers, 42 views summation permutation index
I would like to calculate a sum over some multi-indices, that follow a specific pattern. $$\sum\limits_{1\le i_1<i_2<...<i_k\le N} A(k,i_1, i_2, ..., i_k).$$ $A$ is a fix expression of the ...

### Total of summed objects of unequal lengths

5 answers, 90 views summation
I obtained {1}+{0,2}+{0,0,1}from a calculation. Now I need to sum these objects and reach 4. How can I do this? I tried ...

### 1 Is there a way to exclude certain numbers in a sequence?

1 answers, 58 views summation integer-sequence

### 1 Summing over a list

1 answers, 80 views summation
I intend to sum a series over two lists which I generate myself. However, my code is not working. What is the best way to do this? Thanks. Find my code below ...

### Solving a sum involving a distribution

0 answers, 65 views summation
Can anyone help me solve this sum? ...

### 2 Why these sums return the same result given seemingly they should be different? [closed]

0 answers, 96 views summation series-expansion
ThisSum[1, {k, 1, Infinity}, Regularization -> Dirichlet]gives -1/2, which is right. This ...

### how can I solve this sum?

0 answers, 42 views summation assumptions
how can I solve this sum?Sum[1/(x[p]-x[q]),{p,1,l},p\[NotEqual]q]I tried these codes but not workin' ...

### Forcing nice positions of summation Σ 's under and overscript in FractionBox

Apologies if this has been asked before. The expression ...

### 1 Summation of terms involving contractions with 3 Levi Civita tensors

I am trying to evaluate this expression: $\epsilon^{abcdef}X^R_a X^S_b X^T_c X^U_d X^V_e X^W_f \epsilon_{RST} \epsilon_{UVW}$ where: $X = \frac{a^2 +b^2-1}{2a} \mathbb 1_6$ and I wrote this code ...

### Compute inner product of using a double sum vector [closed]

1 answers, 83 views replacement summation series-expansion

### 2 How to evaluate $\sum_{i=1}^{n-k+1} i \binom{n-i}{k-1}$ to get $\binom{n+1}{k+1}$?

0 answers, 51 views simplifying-expressions summation
I evaluate the following summation using mma (Version: 11.2.0.0): $$\sum_{i=1}^{n-k+1} i \binom{n-i}{k-1}$$ ...

### 1 Sum of part of a list that increases in length

I have a list of numbers whose length increases by 1 for every iteration of a loop. I need to take the sum of the last 5 elements of the list, and if the list's length is smaller than 1 I need to have ...

### 2 Nested ordered summation

1 answers, 55 views dynamic summation time-series

### 10 How can I compute a Kronecker sum in Mathematica?

3 answers, 1.031 views matrix summation

### Algorithm for Swapping indices and simplifying the summand in a double sum [closed]

Say we have something like $$\sum_{p}^N\sum_{q}^N \cos(p) \sin(q) - \cos(q)\sin(p)$$ usually, in the case like this, the indices p and q can be swapped, and the sum simplifies to 0. I have an ...

### 9 Problem with simplification KroneckerDelta

2 answers, 111 views bugs simplifying-expressions summation
Bug introduced in 8.0 or earlier and fixed in 9.0 I have: ...

### 2 Compute symbolic Expectation of a summation

I am required to computed following Expectations : $E[\displaystyle\sum\limits_{i=1}^N \frac{X_{i}}{N}] = \bar{x}_{0}$ & \$E[\displaystyle(\sum\limits_{i=1}^N \frac{X_{i}}{N})^2] = \frac{(N\bar{x}...

### 2 How to make lists the same size?

2 answers, 90 views list-manipulation summation
I want to add 19 lists together and then average over them but they are of unequal length. How do I make then all the same length? i.e. make them all the length of the smallest one. My lists are ...

### 2 How to plot this double sum? [duplicate]

1 answers, 72 views plotting special-functions summation
I want to plot solution of some physics problem that I solved (for r between 1 and 2 and for f between 0 and Pi). I tried it myself but since I am beginner in using Wolfram Mathematica I have not ...

### 1 Plotting Solution to Heat Equation

By hand, I've solved the heat equation and looking to 3D plot the solution. My function is $$2\sum_{n=1}^{\infty}\frac{(-1)^n}{n}\sin(nx)e^{-111n^2t}$$ The code I've been trying to use to far is<...

### A simple code for conditional double summation?

2 answers, 82 views summation conditional
I wrote a code as follows ...