# Items tagged with summationsummation Tagged Items Feed

### Equation with summation...

April 01 2016
1 3

How can Maple solve that problem for me?

Given: a summation of one equation with its limits, equaling another summation with given limits, but NOt the equation. How do Maple be programmed to find that out?

fx     [sum(x^(n)*y^(1-n), n=0..10, = sum(unknownequation),n=1..11)]   , find the unknown equation by maple?

### Manipulating Series Equations...

February 09 2016
3 5

How do I multiply the 4x into the summation to get    and same idea for the 3rd third?

Also, how do I go from     to    by manipulating the indices?

### How to take derivative of sum?...

January 31 2016
1 9

I have the following expression.

What I want to do is take the derivative of this expression with respect to,

Where L is somewhere between 1 and n.

Using the diff operator, I would like to get something like,

But I don't.  Instead, I get zero.  I want to leave n undefined so that the summation isn't automatically expanded out to alot of terms, thereby making it much more difficult to read.  This is especially true as my formulas become more complicated.

Thanks!!

### Nice harmonic sum ...

January 05 2016
0 1

Find S=1+1/2+1/3+1/4+...+1/n ,n is integers .

### Сurse of dimensionality...

December 01 2015
1 1

I'm trying to solve a system of equations thats expressed as a summation (the original has the summation symbol as opposed to 'sum'):

d_actual := solve(W_actual = sum(W_guess(def-asp_rad_inverse[i], E, asp_rad[i]), i = 1 .. n), def);

When n<5, I get an answer after a few seconds, but when n is higher, the program sits and 'evaluates' forever...I've waited up to 30 min.

Background:

I have a plate with a number of hemispheres on the surface (# of impacted hemispheres given a force = n). Each has a unique radius and they're listed from largest to smallest in 'asp_rad[]'. I have an equation for the deflection of a single hemisphere as a function of Force and material properties that I have rearranged with respect to Force (W_guess(deflection, E, r)). There's an opposing plate that stays parallel to the original plate while pushing down on the asperities with Force W_actual. The total deflection of the opposing plate is the sum of: 1) the difference between the tallest radius and the impacted radius in question (asp_rad_inverse[]), and 2) the deflection of the impacted radius in question.

I'm attempting to solve for the total deflection of the opposing plate via solving for the 'def' in the summation above, but when I run it, the program is not able to compute a solution.

### Problem with solving system...

November 16 2015
0 2

How can I solve the following system in Maple for $S_1$ and $S_{i+1}$? I have the code written, but it is giving me nothing as output.

eq1 := Q-A*S[1]*C/X+B*D*(sum(S[j], j = 2 .. i+1))/Y-r[1]*S[1] = 0;
eq2 := A*S[i-1]*C/X-A*S[i]*C/X-B*S[i]*D/Y-r[1]*S[i] = 0;
eq3 := A*S[i]*C/X-B*S[i+1]*D/(Y+S[i+1])-r[2]*S[i+1] = 0;
solve({eq1, eq2, eq3}, {S[1], S[i+1]});

The only non-constants in the system are the $S_j$'s for $j = 1, \ldots, i+1$.

Here is the system in math mode:
$$Q-\frac{AC}{X}S_1-r_1 S_1 +\frac{BD}{Y}\sum\limits_{j=2}^{i+1}S_j = 0 \\ \frac{AC}{X}S_{i-1} - \frac{AC}{X}S_i - \frac{BD}{Y}S_i - r_1 S_i = 0\\ \frac{AC}{X}S_i - \frac{BD S_{i+1}}{Y+S_{i+1}} - r_2 S_{i+1} = 0$$

I have a head start on it by hand, but it's too cumbersome to complete.

Basically, my strategy is to solve for $S_{i+1}$ as a function of $S_1$ and some constants. Then to plug in $S_2, \ldots, S_{i+1}$ in the summation and solve for $S_1$ as a function of constants. Then I would obtain $S_{i+1}$ as a function of constants itself.

Thanks for any help.

### How can I animate this stiff function?...

September 28 2015
1 4

Hi,

I have a problem with creating a function contains n-dimensional independent variables with random function .. The function looks like:

where U is a random between 0 and 1

For 1-dimensional problem, it will be like:

The plot by MATLAB will be:

While, for 2-dimensional problem, it will be like:

and the plot with MATLAB will be:

The MATLAB code is:

x1min=-5;
x1max=5;
x2min=-5;
x2max=5;
R=1000; % steps resolution
x1=x1min:(x1max-x1min)/R:x1max;
x2=x2min:(x2max-x2min)/R:x2max;

for j=1:length(x1)

% For 1-dimensional plotting
f1(j)=rand*abs(x1(j));

% For 2-dimensional plotting
for i=1:length(x2)
fn(i)=f1(j)+rand*abs(x2(i))^2;
end

fn_tot(j,:)=fn;

end

figure(1)
plot(x1,f1);

figure(2)
meshc(x1,x2,fn_tot);

I have used Maple because of its great graphics and animation, and for the mathematical analysis capability. However, to animate the above problem for 1- and 2-dimensional problems, I always fail!

My attempt has been just successed to plot 1-dimensional problem (without animation) .. And it tooks long-time with many codes!

restart;

X := Statistics:-RandomVariable(('Uniform')(0, 1));
R := Statistics:-Sample(X, 1000);

Vect := abs(Vector[column]([seq(0 .. 10, 10/999)]));

V := ~[-](Vect, 5);

with(LinearAlgebra);
Mat := Multiply(V, R);

with(ArrayTools);
f := ArrayTools:-Diagonal(Mat);

F := abs(f);

Axis := Transpose(V);

f5 := plot(Axis, F, style = line);

And finally I got the graph:

But the problem is:

How can I animate it? Maybe I need to express it with new Maple code?

How can I plot and animate it when n=2?

Thanks

### Summation in different form...

September 11 2015
3 15

Dear Feinds,

How can I compute a double summation of the following form in Maple.

∑5m=1  ∑j+k=m-1 (2m (Dk(a_m*f)) (Dj(f)))

where Drepresents nth order derivative.

EDIT 1

EDIT 2

Function "f" in the first derivative is changed to "a_m*f" where a_m (variable coefficients) represents any function of x.

First of all thank you so much for all the nice answers.

Here, the notation a_m doesn't work as I was expecting and then I thought let's just make it a(m) for simplicity, it seemed to work fine but unfortunatelyassumes it as a constant function. How can I rectify this problem?

### Help in unsupported type of index with Summation...

May 28 2015
2 5

Hi, I'm having a problem regarding this equation:
sum(v(i), i = 1 .. 28)

where, v is a Data Table created under the Components Tab with 28 Rows, and 1 Column.

I keep on getting an error of:

Error, unsupported type of index, i

I didn't use or declare 'i' in any part of the program.

### How to efficiently write a formula in Maple...

May 14 2015
1 5

Let M and K be given positive integers.

I struggle with how to write efficiently this formula in Maple,mainly because it sums over *pairs* of integers K1 and K2, with the given property that "K1+2*K2=K":

0<=K1<=K,

0<=K2<=K/2

sum { M!/(M-K1-K2)! * K!/(K1! * K2)! * 1/M^K * 1/2^K2 : such that K1 + 2*K2 = K}

The "!" means factorial.

### how to make desired polynomials with sum of the po...

March 09 2015
1 2

hi everyone.how can i write a function or procedure or summation so that i can write down the following polynomial ? i just want to create a set of polynomials which their summation of power ( power of x + power of y ) be less than three or equal to three ? the coefficients priority is not important , for example it is not important that a1 multiplies to x or y , i just want to create this polynomial with some coeeficients. tnx for help

 > restart:
 > a[9]*y^3+x^3*a[8]+x^2*y*a[5]+x*y^2*a[7]+x^2*a[2]+x*y*a[4]+y^2*a[6]+x*a[1]+y*a[3]+a[0];
 (1)
 >

### find sigma!!!!!!!!!!!!!!!!!!!...

March 08 2015
0 1

Sum(a^(k/a^k), k= 1..n);

### Is this double sum over a binomial in error?...

October 31 2014
3 8

Maple returns the wrong answer to the following very simple double sum:

T:=(x,m)->sum( sum(binomial(m,k+p),k=1..m-p)*x^p,p=0..m-1);

Maple gives zero for all m>0.  However, the correct answer is a non-zero polynomial in x.

For example, with Maple:

T(x, 3);
0

It would be helpful if others can check this double sum in their version of Maple and report results.

### how to count the number summation ...

August 15 2014
1 10

RandomCompositions:= module()
local
Compositions, Rand,

RandomCompositions:= module()
local
Compositions, Rand,
ModuleApply:= proc(n::posint, k::posint)
local C;
Compositions:= [seq(C-~1, C= combinat:-composition(n+k, k))];
Rand:= rand(1..nops(Compositions));
()-> Compositions[Rand()]
end proc;

end module:
R:= RandomCompositions(8,6):
seq(R(),i=1..10);

[0, 0, 2, 6, 0, 0], [1, 0, 0, 3, 4, 0], [0, 3, 3, 2, 0, 0],[1, 2, 4, 0, 1, 0], [0, 4, 0, 1, 3, 0],

[2, 0, 1, 4, 1, 0],[2, 0, 1, 1, 3, 1], [1, 0, 4, 2, 1, 0], [1, 3, 0, 2, 0, 2],[2, 0, 3, 2, 1, 0]

with(Statistics):
Tally(R());
[0 = 1, 1 = 4, 4 = 1]

I want to count the 0 to 8 respectively summation,and divide by i.

But the  seq command  R() isn't conform  with Tally command R() .

Thanks.

### how to set random summation...

August 06 2014
1 5

a:=rand(0..8):
b:=rand(0..8):
c:=rand(0..8):
d:=rand(0..8):
e:=rand(0..8):
f:=rand(0..8):
a()+b()+c()+d()+e()+f()=8;

This is my  programming code.

I want ot set six random summation is  8.

But the random summation can't reach 8.

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