Is this an expected behaviour for simplify/size? 

I was simplifying a result from pdsolve, but did not check that the solution was null or () before calling simplify.

It turns out that  simplify((),size)  returns size for this. I find this is very strange.

I would have expected it to return ().

I can fix this by checking that sol is not null before calling simplify ofcourse. But the question is, why does simplify((),size) return size? What is the logic for this? From help:

The simplify(expr, size) calling sequence is used to attempt simplifying the expression size, performing only collections and simple decomposition of fractional powers in the coefficients - sometimes taking advantage of linear factors when they exist. No other mathematical simplifications of the expression or its subexpressions is performed. These operations, while simple and with low computational cost, may remarkably structure the expression and reduce its size.
 

is it possible what happens is this: becuase "sol" was null, the call simplify(sol,size) has actually become simplify(size) and the result is size.  So because the first slot in the call was (), it was ignored during the call and the first parameter became size insteal of sol?

Maple 2019 on windows 10.

I googled, read help and not able to find how to do this. 

I want to change the zoom in worksheet to any value I want, and not just 100%,150%,75%, etc.... which are the values that are listed in View->Zoom factor.

Is there a place one can type in the zoom value they want? Say 110% or any other number?

windows 10.

Thank you

I read a string from file which contains a sequence of Maple commands, all in one string. The commands are separated by ";" in the string. I need to then evaluate all the commands in the string as if I typed them one after the other. 

Here is an example

data:="x:='x';y:='y';sol:=dsolve(diff(y(x),x)=1,y(x));"; #read from database
parse(data);

Warning, extra characters at end of parsed string
x := 'x'
 

I want the result to parse to be as if I typed

x:='x'; 
y:='y'; 
sol:=dsolve(diff(y(x),x)=1,y(x));

I looked at help in parse page, but I do not see what I need to do. It says that 

If the option 'statement' is specified, the string must consist of exactly one Maple statement (which includes expressions). The statement is parsed and evaluated, and the result is returned.
 

But I am not using the statment option. I also tried using this option, no change, same problem.

Is there a way to prase such a string? 

Thanks

Is this documenation wrong?

https://www.maplesoft.com/support/help/maple/view.aspx?path=Database%2fSQLite%2fFetchRow

It says that calling sequence is 

     FetchRow( statement, column, valuetype  )

But below it only shows 

With no column anywhere.  And none of examples show column in them.

And when I tried it by adding a column name that I know exist in my sqlite3 database, Maple gave an error that no such parameter allowed.  

Does FetchRow support column name or is the above just a documenation error?

Maple 2019

Hello Maple experts;

I am not able to understand why Maple 2019 can solve Laplace PDE in 2D Catersian on semi-infinite domain, when the infinity is along the Y direction, but not along the X direction, since the solution method is exactly the same.

Here is the code

restart;

#right one, Maple can not solve
pde := diff(u(x, y), x$2)+diff(u(x, y), y$2) = 0:
bc_left_edge := u(0, y) = 0:
bc_bottom_edge:= u(x, 0) = 0:
bc_top_edge:= u(x, 1) = A:
bc:=bc_left_edge ,bc_top_edge,bc_bottom_edge:
sol:=pdsolve([pde, bc],HINT = boundedseries(x = infinity)) assuming x>0,y>0;


#left one, Maple can solve
pde := diff(u(x, y), x$2)+diff(u(x, y), y$2) = 0:
bc_left_edge := u(0, y) = 0:
bc_bottom_edge:= u(x, 0) = 0:
bc_right_edge:= u(1, y) = A:
bc:=bc_left_edge ,bc_right_edge,bc_bottom_edge:
sol:=pdsolve([pde, bc],HINT = boundedseries(y = infinity)) assuming x>0,y>0;

Here is screen shot.

Maple can solve both cases if I remove the HINT. But the solution it gives is not as simple as using the HINT and contains unknown constants (_C5) that is why I use the HINT.

But the main question is, since both problems are exactly the same, why Maple can solve one and not the other when using the HINT? Is there something I am doing wrong? 

Maple 2019 on windows 10 and Physics cloud version 333.

Thank you