I have thought that   D(y)(0)=C1  and  eval(diff(y(t),t),t=0)=C1  mean exactly the same thing which is derivative of y wr.t. "t" evaluated at specific point t=0 is C1.

If you agree they are exactly the same thing, then why dsolve works with both forms used for initial conditions if the option 'series' is not used.

When using the 'series' option, dsolve stops working when using  eval(diff(y(t),t),t=0) form? All else is the same.

ode:=diff(y(t),t$2)+3*diff(y(t),t)+2*y(t)=0;
bc_form_1:=y(0)=C1,eval(diff(y(t),t),t=0)=C2;
bc_form_2:=y(0)=C1,D(y)(0)=C2;
sol1:=dsolve([ode,bc_form_1],y(t));
sol2:=dsolve([ode,bc_form_2],y(t))

Both the above work

But now when I use the 'series' option, the first form stops working!

ode:=diff(y(t),t$2)+3*diff(y(t),t)+2*y(t)=0;
bc_form_1:=y(0)=C1,eval(diff(y(t),t),t=0)=C2;
bc_form_2:=y(0)=C1,D(y)(0)=C2;
sol1:=dsolve([ode,bc_form_1],y(t),'series');
sol2:=dsolve([ode,bc_form_2],y(t),'series')

Is this a bug? 

Just updated to Maple 2019.1  on windows 10.

I have reinstalled Maple 2019 several times, including its latest update. But when trying to graph the following:

plot(sin(x), x = -2*Pi .. 2*Pi)

But I get this:

Error, (in plot) expected a range but received x = -2*Pi .. 2*Pi

And if I enter:

sin(x)

The result is:

2.73949338633639*10^-116 + 2.73949338633639*10^-116*I

When trying this:

plot3d(x*exp(-x^2 - y^2), x = -2 .. 2, y = -2 .. 2, color = x)

I get this:

And if I try it with Graph Theory:

with(GraphTheory);
G := Graph({{a, b}, {a, c}, {b, c}});
G := Graph 1: an undirected unweighted graph with 3 vertices and 3 edge(s)

DrawGraph(G)

Error, (in GraphTheory:-DrawGraph) invalid input: modp received I, which is not valid for its 2nd argument, m
 

I do not know what is the reason for this anomalous behavior of Maple 2019, it will be some software bug or it will be an error caused by my computer...
I would like to know if this problem happens to other people or just to me. Any help or guidance on this problem will be greatly appreciated.

Best regards

In Maple 2019 it is not possible to change to "1-D Math Input".

But it is possible to convert (right mouse->convert to-> 1D Math Input)

In this mode I get the following results:

If I do:

The font that Maple uses for the Tablulate is much larger than the font used to display the Dataframe. How does one choose the font size that Tabluate() uses? 

Peter

As always, thank you all in advanced.

I found this challenge by chance.

solve 615+x^2=2^y over integers.

I rushed to Maple and tried to solve it  with “solve” and "assuming" but I did not get results.

solve(615+x^2=2^y) assuming x::integer,y::integer   did not work.

How could this equation be suitably formulated for Maple to solve it?
 

Good day,

I was recently using Maple 2019 for work on a project, and ran into an error. This error (which will be copied and pasted below for others to test) occurs when making assumptions across multiple lines (whether using the additionally function or not) while using IntegrationTools[Change]. It seems that, if during the process a variable that was within both the assumptions is subtracted from itself, the subtraction fails to happen and leaves what effectively equals 0 in the workings, making further workings impossible.

I'm wondering if anyone else is able to reproduce this error? I know the fix for it is to not disjoint the assumptions, but I am curious if others can easily reproduce it or if others have experiences with it!

As promised, below you will find my workings in order to reproduce this error!

Base Error:

restart;
assume(a>0,b>0,b>a,c>0,t>0);
interface(showassumed=0);
F := Int(sqrt(d-a*c^2*t),d=0...infinity);
assume(b>a);
IntegrationTools[Change](F,-a*t*c^2+d=-y,y)

Simple Fix:

restart;
assume(a>0,b>0,b>a,c>0,t>0);
interface(showassumed=0);
F := Int(sqrt(d-a*c^2*t),d=0...infinity);
IntegrationTools[Change](F,-a*t*c^2+d=-y,y)

Error Without Interface Change:

restart;
assume(a>0,b>a,c>0,t>0);
F := Int(sqrt(d-a*c^2*t),d=0...infinity);
assume(b>a);
IntegrationTools[Change](F,-a*t*c^2+d=-y,y)

Error When Using Additionally:

restart;
assume(a>0,b>a,c>0,t>0);
interface(showassumed=0);
F := Int(sqrt(d-a*c^2*t),d=0...infinity);
additionally(b>a);
IntegrationTools[Change](F,-a*t*c^2+d=-y,y)

Dear Maple friends~

Recently I am thinking a question about how to use Maple to prove an equation based on a known partial differential equationand its boundary conditions.

Although I can Prove it with hand computation ,it still has some difficulty and it will be really hard if its partial differential equation become more complex(As a matter of fact, it will happen).So I think of Maple and want to take advantage of computer.However,I get few ideas how to realize it .The details are as follows：

alias(u=u(x,t)):
pde:=diff(u,t)-diff(u,x$2,t)+4*u^2*diff(u,x)=3*u*diff(u,x)*diff(u,x$2)+u^2*diff(u,x$3);
N:=5;#actually N can be any positive integer!
bcs:=eval(u,x=-infinity)=0,seq(eval(diff(u,x$ha),x=-infinity)=0,ha=1..N),eval(u,x=infinity)=0,seq(eval(diff(u,x$ha),x=infinity)=0,ha=1..N);
E:=Int(u^4+2*u^2*diff(u,x)^2-diff(u,x)^4/3,x=-infinity..infinity);

#try to prove the following equation
diff(E,t)=0

The written proof is as follows:

Therfore,I submit such a problem and look forward your solutions and suggestions sincerely~

restart;
with(Physics);
with(LinearAlgebra);
N := 4;


Cf := Matrix(6, 6, (z, p) -> C[z, p, 1], shape = symmetric);
sigma[1] := Vector(6, [sigma[1, 1, 1], sigma[2, 2, 1], sigma[3, 3, 1], sigma[1, 2, 1], sigma[1, 3, 1], sigma[2, 3, 1]]);
varepsilon[1] := Vector(6, [varepsilon[1, 1, 1], varepsilon[2, 2, 1], varepsilon[3, 3, 1], gamma[1, 2, 1], gamma[1, 3, 1], gamma[2, 3, 1]]);
sigma[1] := Cf . (varepsilon[1]);





for i from 2 to N do
    C[i] := Matrix(6, 6, (z, p) -> C[z, p, i], shape = symmetric);
    sigma[i] := Vector(6, [sigma[1, 1, i], sigma[2, 2, i], sigma[3, 3, i], sigma[1, 2, i], sigma[1, 3, i], sigma[2, 3, i]]);
    varepsilon[i] := Vector(6, [varepsilon[1, 1, i], varepsilon[2, 2, i], varepsilon[3, 3, i], gamma[1, 2, i], gamma[1, 3, i], gamma[2, 3, i]]);
    sigma[i] := (C[i]) . (varepsilon[i]);
end do;



B[1] := 0;

for i to N do
    Parameters(epsilon11c, C[1, 1, i], C[1, 2, i], C[2, 2, i], C[2, 3, i], R[i], A[i], B[i + 1], P);
end do;



g[1](r);
ux[1] := (x, r) -> epsilon[1][1]*x + g[1](r);
ur[1] := r -> A[1]*r + B[1]*1/r;
varepsilon[1][1] := epsilon11c;
varepsilon[1][2] := r -> (A[1]*r + B[1]*1/r)*1/r;
varepsilon[1][3] := r -> diff(ur[1](r), r);
varepsilon[1][3](R[2]);



for i from 2 to N - 1 do 
g[i](r); 
ux[i] := (x, r) -> epsilon[i][1]*x + g[i](r); 
ur[i] := r -> A[i]*r + B[i]*1/r; 
varepsilon[i][1] := epsilon11c; 
varepsilon[i][2] := r -> (A[i]*r + B[i]*1/r)*1/r; 
varepsilon[i][3] := r -> diff(ur[i](r), r); 
varepsilon[i][2](r); i;
end do;
i;
varepsilon[2][2](r);

Hi everyone,

I am currently writing a code on maple and I am finding difficulties in this section.

When I define the functions this way, the result I get from the loop "for" for varepsilon[i][2](r) is the same and doesnt depend on i value. I also tried to define it another way that would give me different results but I would end up with being unable to replace the variable "r" with its values (I would get r(R2)).

I would be grateful if you could advice me with this matter.

Thank you in advance.

Hi,

I want to figure out if the Student license offered by Maplesoft for Maple 2019 is perpetual or is just lasts for a year? If it lasts for just 12 months, is there another license I should get which isn't as expensive as the full license? I need it for my personal research. 

Maple is very good in solving PDE's. But this specific solution seems way too complicated when compared to Matematica solution, which I verified using Maple pdetest to be correct.

Is there a way to make Maple produce the simpler solution to this pde? simplify does nothing on the solution. May be by using a good HINT or such other option? 
 

Here is screen shot showing the other solution

Download q1.mw

How do I get Maple to factorize this simple expression without too much effort?

f:=3/2 + sqrt(8*k + 2) + 2*k

Is the following a bug? I am using Maple 2019  64 bit with latest Physics package 357 on windows 10.

Download bug2.mw

I just noticed with chagrin that one of my favorite menu commands, Edit -> Remove output -> From worksheet, is missing from Maple 2019's Standard GUI. Is there a keyboard command or toolbar item to replace it?

Hello everyone, Greetings!

I am facing a really strange problem. I need to write an expression, however, maple out of nowhere assigns values to the variable used. only to those which are written inside sin (). In previous versions the out put is fine. Is there a new way to write expressions in maple 2019? I am not sure.

Download strngmpl.mw

I have encountered the situation frequently where I want to simplify an equation by cancelling out terms on both sides.  I have tried simplify() with a variety of assumptions(J,L>0,etc) and I haven't been able to get it to work.  On a simple equation, one can use 'solve' however there are situations where solve doesn't work and I just want to simplify the equation not solve it.

The script below shows the situation.  I cancel out JL and the complex exponential by manually identifying that they are common factors.  Is there an automatic way of doing this type of simplification?

If I use expand() it clearly shows the common factors on both sides but I haven't found the command that removes any common terms.

Download common_factors.mw