Hi,

I try to remove first column from my df variable, but the command Remove(df,1) don't work. Ideas ?

Thanks

SérieTabulateStat.mw

hello 

I am beginner in maple.

I have a differential equation system with 17 equations. I used dsolve() function and my code worked.

Now, I want to integral from the dsolve answer.but I dont know how?

Hi, how to generate a matrix ( 6X2) with different random integers  ( between 10 and 20) in the first column and others random integers ( between 50 and 100) in the second column ?

Thanks

SérieTabulateStat.mw

Is it possible in one worksheet of a workbooks to access variables or embedded components in another worksheet programmatically?

As far as I can see it is possible to save and restore variables through the variable browser, so it is also possible to get them from one worksheet to another. This is however done by the user.

Now the question is, if it is somehow possible to e.g. access the contents of a embedded component like a Combobox in a different worksheet of the workbook - without opening the worksheet first?

[[1,1,["ab","xy"]], [0,1,["xy"]]]
 

how to sort by first number , second number , and list of string ?

how to count and group by third list of strings having first two number 0,0 or 0,1 or 1,0 or 1,1 

for example 

["xy"] at most count 4  , at least count 1

would like to find which is [1,1,... ] and only count 1

Is Prüfer's algorithm available in Maple (given a tree, produce the code, and vice versa)? If not, has anyone written the code for it?

Hello

I need to check if the solution of a polynomial system (for instance a set of polynomial equations in y and z) using two different approaches is the same (equal or symmetric).  I thought if I use simplify plus abs I could solve the problem, but that is not the case.   Here is an example;

The first method returns the following solution:

aa := {{y = -2*X1*X2*alpha[1, 8]*alpha[2, 6]/(sqrt((X1^4*alpha[1, 8]^2*alpha[2, 4]^2 + 2*X1*((-2*X1*X2*alpha[3, 6] - 2*X2*alpha[2, 2] + 2*X3)*alpha[2, 6] + X1*X2*alpha[2, 4]*(alpha[2, 8] + alpha[3, 9]))*alpha[1, 8] + X2^2*(alpha[2, 8] + alpha[3, 9])^2)*alpha[1, 8]^2) + alpha[1, 8]^2*alpha[2, 4]*X1^2 + X2*alpha[1, 8]*(alpha[2, 8] + alpha[3, 9])), z = (-sqrt((X1^4*alpha[1, 8]^2*alpha[2, 4]^2 + 2*X1*((-2*X1*X2*alpha[3, 6] - 2*X2*alpha[2, 2] + 2*X3)*alpha[2, 6] + X1*X2*alpha[2, 4]*(alpha[2, 8] + alpha[3, 9]))*alpha[1, 8] + X2^2*(alpha[2, 8] + alpha[3, 9])^2)*alpha[1, 8]^2) - alpha[1, 8]^2*alpha[2, 4]*X1^2 + (-alpha[3, 9] - alpha[2, 8])*X2*alpha[1, 8])/(2*alpha[1, 8]^2*alpha[2, 6]*X1)}, {y = -2*X2*alpha[1, 8]*alpha[2, 6]*X1/(-sqrt((X1^4*alpha[1, 8]^2*alpha[2, 4]^2 + 2*X1*((-2*X1*X2*alpha[3, 6] - 2*X2*alpha[2, 2] + 2*X3)*alpha[2, 6] + X1*X2*alpha[2, 4]*(alpha[2, 8] + alpha[3, 9]))*alpha[1, 8] + X2^2*(alpha[2, 8] + alpha[3, 9])^2)*alpha[1, 8]^2) + alpha[1, 8]^2*alpha[2, 4]*X1^2 + X2*alpha[1, 8]*(alpha[2, 8] + alpha[3, 9])), z = (sqrt((X1^4*alpha[1, 8]^2*alpha[2, 4]^2 + 2*X1*((-2*X1*X2*alpha[3, 6] - 2*X2*alpha[2, 2] + 2*X3)*alpha[2, 6] + X1*X2*alpha[2, 4]*(alpha[2, 8] + alpha[3, 9]))*alpha[1, 8] + X2^2*(alpha[2, 8] + alpha[3, 9])^2)*alpha[1, 8]^2) - alpha[1, 8]^2*alpha[2, 4]*X1^2 + (-alpha[3, 9] - alpha[2, 8])*X2*alpha[1, 8])/(2*alpha[1, 8]^2*alpha[2, 6]*X1)}}

and the second Method:

bb := {{y = -2*X2*alpha[2, 6]*X1/(-sqrt(X1^4*alpha[1, 8]^2*alpha[2, 4]^2 + 2*X2*alpha[1, 8]*((alpha[2, 8] + alpha[3, 9])*alpha[2, 4] - 2*alpha[2, 6]*alpha[3, 6])*X1^2 - 4*alpha[1, 8]*alpha[2, 6]*(X2*alpha[2, 2] - X3)*X1 + X2^2*(alpha[2, 8] + alpha[3, 9])^2) + (alpha[2, 8] + alpha[3, 9])*X2 + alpha[1, 8]*alpha[2, 4]*X1^2), z = (sqrt(X1^4*alpha[1, 8]^2*alpha[2, 4]^2 + 2*X2*alpha[1, 8]*((alpha[2, 8] + alpha[3, 9])*alpha[2, 4] - 2*alpha[2, 6]*alpha[3, 6])*X1^2 - 4*alpha[1, 8]*alpha[2, 6]*(X2*alpha[2, 2] - X3)*X1 + X2^2*(alpha[2, 8] + alpha[3, 9])^2) - alpha[1, 8]*alpha[2, 4]*X1^2 + (-alpha[3, 9] - alpha[2, 8])*X2)/(2*alpha[1, 8]*alpha[2, 6]*X1)}, {y = -2*X2*alpha[2, 6]*X1/(sqrt(X1^4*alpha[1, 8]^2*alpha[2, 4]^2 + 2*X2*alpha[1, 8]*((alpha[2, 8] + alpha[3, 9])*alpha[2, 4] - 2*alpha[2, 6]*alpha[3, 6])*X1^2 - 4*alpha[1, 8]*alpha[2, 6]*(X2*alpha[2, 2] - X3)*X1 + X2^2*(alpha[2, 8] + alpha[3, 9])^2) + alpha[1, 8]*alpha[2, 4]*X1^2 + (alpha[2, 8] + alpha[3, 9])*X2), z = (-sqrt(X1^4*alpha[1, 8]^2*alpha[2, 4]^2 + 2*X2*alpha[1, 8]*((alpha[2, 8] + alpha[3, 9])*alpha[2, 4] - 2*alpha[2, 6]*alpha[3, 6])*X1^2 - 4*alpha[1, 8]*alpha[2, 6]*(X2*alpha[2, 2] - X3)*X1 + X2^2*(alpha[2, 8] + alpha[3, 9])^2) - alpha[1, 8]*alpha[2, 4]*X1^2 + (-alpha[3, 9] - alpha[2, 8])*X2)/(2*alpha[1, 8]*alpha[2, 6]*X1)}}

Notice (if I am not mistaken) that the first pair of the first solution is equal to the second pair of the second solution.   If I compare them using evalb(simplify(aa[1,1])=simplify(bb[2,1])), Maple returns false.  Again, if I am not mistaken I think they are the same.

a) How can the solutions be compared?

b) I also need to determine if there are symmetric roots in a set of solutions (either in aa or in bb) and a procedure that returns just one solution.  Something like:

func:=(auxsolsx,varsx)->`if`(nops(map(v->op(map(w->abs(subs(w[ListTools:-Search(v,varsx)],v)),auxsolsx)),varsx))=2,ifelse(nops(auxsolsx)=1,auxsolsx,{auxsolsx[1]}),NULL):

Many thanks

Hi,

I try to represent the successive derivatives of a function using a tabulation . How do I insert titles in the seq command options?

Thanks

QuestionTabulation.mw

Apparently when raising an error exception, Maple stops further code.

Is there any possibility to just show a popup message, and then continue with the code after the message?

ErrorGoOn.mw

hello i startet using subs. and i got a problem, my expression is only finished and valid if it stands in the factorised version. i am calculating some koefficients and then with subs i am trying to insert it back into the original expression. but it always expand and simplyfy. looking at it, i can see it is a oneway arrow => after the simplicifaction, so it is impossible to rearrange.

what i would like it to happen is the expression i am asking subs to insert a koefficient into is insertet only, and not evaluated and rearrange. can i use a tecknique er something to stop the evaluation and only perform an insertion.

my equation are

a*(2*A + 2*B) + b*(C) = c*(2*A + B) + d*(B*2) + e*(C + 4*B)

i have calculated the koefficients as

{a = 6, b = 1, c = 6, d = 1, e = 1}

i would like it to look like this when i use subs

6*(2*A + 2*B) + 1(C) = 6*(2*A + B) + 1*(B*2) + 1(C + 4*B)      

but it looks like this

12*A + 12*B + C = 12*A + 12*B + C

How to determine populations y for which y ' = 0? 

Have no idea about solving Newton's law of cooling in maple. 

Is anyone can help me? Thanks! 

Hello!

I have a function, say f(x,y), and I want to solve for x for a range of values of y. The function is complicated, and thus, I gather I need to use fsolve to find the set of solutions numerically. I know how to use fsolve to find x for a given (single) value of y, but I have never used it to generate a list of x values given a range of y values. Then, I would l like to plot x as function of y, but I will leave that for later.

Thank you!

Hello!
Is there a way i can plot these two functions in one graph?

Suppose we have a 200-litre tank. Suppose 10 litres per minute of salt water (brine) flows into the tank at the top, it mixes perfectly with the contents of the tank, and 10 litres per minute of the mixture flows out of the tank at the bottom. Assume for simplicity that the salt water in the tank is stirred so that its concentration is uniform in the tank. Let S(t) be the amount of salt, in grams, in the tank at t time minutes. Suppose the salt water flowing into the tank has concentration 80 grams per litre.

Find the differential equation to model the change in S(t).

Assuming that at t = 0 time the concentration of salt in the tank is 10 grams per litre, solve the differential equation using Maple.

What is S(infinite)? That is, how much salt is in the tank after a long time?

Now graph S(t) for a suitable domain so we can see the function approaching the value S(infinite)

---------------------

Have some difficulty to understand the problem. I mean, such modelling problem rather than pure math computation.

Thank you so much!