## if condition inside eval and sum...

I really want to use if condition inside of eval and sum, example as below:

sum(eval(y=x^(j),(if j=1 then x=2 else x=3 fi)),j=1..2)

The reason is: the value of x to be evaluated depends on the value of j which differs inside of the sum (in the context of B-spline functions).

Any lights? Thanks,

## how must i write this formula?...

any idea for my problem?

> k1 := sum(X[h, t], t = 1 .. 23) >= 9;
9 <= X[h, 1] + X[h, 2] + X[h, 3] + X[h, 4] + X[h, 5] + X[h, 6]

+ X[h, 7] + X[h, 8] + X[h, 9] + X[h, 10] + X[h, 11] + X[h, 12]

+ X[h, 13] + X[h, 14] + X[h, 15] + X[h, 16] + X[h, 17]

+ X[h, 18] + X[h, 19] + X[h, 20] + X[h, 21] + X[h, 22]

+ X[h, 23], h = 1 .. 6

why 'h' still 'h'. from my textbooks the formula must be like this :

## solve a system of equation numericlly ...

i want to solve the system of equation ( 1 )  , (2)  ,  (3)   under the assumation that x , y have the CDF in (4)  ,  (5)

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## SEEMOUS 2017

by: Maple

Here is a problem from SEEMOUS 2017 (South Eastern European Mathematical Olympiad for University Students)
which Maple can solve (with a little help).

For k a fixed nonnegative integer, compute:

Sum( binomial(i,k) * ( exp(1) - Sum(1/j!, j=0..i) ), i=k..infinity );

(It is the last one, theoretically the most difficult.)

## Code works fine in Maple 18 and Maple 2015 but not...

I have the following function which came from a collaborator of a collaborator. It computes a generating function for a family of function's we're using.

```GF_Generate := proc (n)
local summand, i, j;
summand := U[0]^x[0]*mul(U[i]^y[i], i = 1 .. n)*mul(binomial(x[0]+add(w[j], j = 1 .. i), y[i])*p^y[i]*(1-p)^(x[0]+add(w[j], j = 1 .. i)-y[i])*binomial(x[0]-1+add(w[j], j = 1 .. i), x[0]-1+add(w[j], j = 1 .. i-1))*v[i]^(x[0]+add(w[j], j = 1 .. i-1))*(1-v[i])^w[i], i = 1 .. n);

for j from n by -1 to 1 do summand := normal(sum(summand, y[j] = 0 .. infinity)) end do;
for j from n by -1 to 1 do summand := normal(sum(summand, w[j] = 0 .. infinity)) end do;

sum(summand, x[0] = 0 .. infinity)
end proc;```

For arguments of 2 and 3 it's quick and works fine on Maple18 (tested both GUI and terminal client on OS X), Maple2015 (tested terminal client only on RHEL linux), but generates a "too many levlels of recursion" error in Maple2016 (tested terminal client only on RHEL linux; same server as Maple2015 was tested). It's slow for arguments of 4 and above (45 minutes for n=4 on my mac laptop), so I haven't tested it thoroughly with larger arguments.

Any idea why this code fails in Maple 2016?

## Problem with finite sum. Negative upper limit...

Hi Dears,

I'm have a code like this:

sum(-GAMMA(k+1, x), k = 0 .. -2) and Maple give me : Ei(1, x).

How to check that answer is correct?

I am looking forward to hearing from you.

## How to expand a double sum for a list of sequences...

Can somebody please expand the following double sum to produce a list of sequences?

(Sum(f[i], i = 0 .. 1))*(Sum(g[i, j, k], j = 0 .. 1)) for k = {1,2}

I need to make sure the operation order is correct, so I would like to verify my workings.

Thanks!

## How to change summation index of Sum from PDE sol...

Hello.

I have a Pde solution in from of the sum.

pde := diff(u(x, t), t) = diff(u(x, t), x\$2)

symbolic := pdsolve([pde, u(x, 0) = 1, u(0, t) = 0, u(1, t) = 0])

symbolic := u(x, t) = Sum(-(2*((-1)^_Z9-1))*sin(_Z9*Pi*x)*exp(-Pi^2*_Z9^2*t)/(Pi*_Z9), _Z9 = 1 .. infinity)

I tried a subs or eval command dosen't work.

Thanks.

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## closed form solution...

I am having issues with Maple 2016 computing closed form solutions using the sum command. For example, sum((-1)^n, n = 1 .. infinity) evaluates to -1/2 in the help topic, however, when I run the command in a maple document, this result is not obtained. It instead returns sum((-1)^n, n = 1 .. infinity). Likewise, sum( a*r^k, k = 0..infinity) doesn't evaluate to -a/(r-1). How can I get Maple to determine closed form solutions for power series?

## double summation problem ...

i wrote this problem to solve

Delta= Sum(j=1 to n)SUM(i=j to n)(pi*hj/Ad(t,ij)*Et,ij))

Where n=70,  G= ftj (t)/(4+0.85*t) , where (t =8, 16, 24,…….up to 8*n), hj= 13 for all j except j1 =18

Mij=ES/E(G),          where E(G)= 57sqrt(1000*G)

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## Writing Series in maple...

f=sum((2*q*cos(2* i*x)*(-1)^(i)*(-1)^((2*i-1)))/(i*Pi),i=1.3.5...35)

I want to write this series but getting error

the result is

2*q*cos(2*x)/Pi-2*cos(6*x)*q/(3*Pi)+2*q*cos(10*x)/(5*Pi)-2*q*cos(14*x)/(7*Pi)+2*q*cos(18*x)/(9*Pi)-2*q*cos(22*x)/(11*Pi)+2*q*cos(26*x)/(13*Pi)-2*q*cos(30*x)/(15*Pi)+2*q*cos(34*x)/(17*Pi)-2*q*cos(38*x)/(19*Pi)+2*q*cos(42*x)/(21*Pi)-2*q*cos(46*x)/(23*Pi)+2*q*cos(50*x)/(25*Pi)-2*q*cos(54*x)/(27*Pi)+2*q*cos(58*x)/(29*Pi)-2*q*cos(62*x)/(31*Pi)+2*q*cos(66*x)/(33*Pi)-2*q*cos(70*x)/(35*Pi)

can anybody help

## Help in add / sum...

Hello, I need help in add/sum, there are two problems:

1. How we write triple summation (sigma) in Maple? (See pic)

2. How we write summation like in this pic?

for e from 1 to 9 do

for k from 1 to 17 do

if i=(2*e-1) then next else

end if

end do

end do

For example, the expected result for e=2 and k=1 is like following equation:

x[2,1,1]+x[2,3,1]+x[2,4,1]+x[2,5,1]+...+x[2,17,1]+x[2,18,1]=1

But the result I get:

x[2,1,1]+x[2,2,1]+x[2,3,1]+...+x[2,18,1]=1

How to omit the x[2,2,1]?

Thank you.

## how do I plot a solution with series representatio...

Hi! I'm trying to find the way to plot the solution with series representation. I need some help to find the easiest way.

Note: I realized some typing errors, which do not change the question a lot ,and I corrected them.

plot.mw

## Airy's stress function (convert the results into s...

Can we calculate the following equations in Maple?

Substituting equations (21) and (22) into (17), and then obtain equation (23). How to do that? I have done this, but the results are complex and large. They are not in a sum form, but in an expansion form. The reference and the maple file are attached.

Best wishes,

Kang

Dynamic_buckling_of_thin_isotropic_plates_subjected_to_in-plane_impact.pdf

gg.mw