I knew him (the son) - I took his Mathematical Logic course when I was a freshman (in the Moscow State University). He was a very good teacher (and I got an A.)

Alec

I knew him (the son) - I took his Mathematical Logic course when I was a freshman (in the Moscow State University). He was a very good teacher (and I got an A.)

Alec

You can check your answer for the original problem in Maple,

pdetest(u(x,t)=(l/Pi)^2*sin(Pi*x/l)*(1-exp(-t/2)*
(cos(sqrt(Pi^2/l^2-1/4)*t)+1/2/sqrt(Pi^2/l^2-1/4)*
sin(sqrt(Pi^2/l^2-1/4)*t))), [PDE,BCs,ICs]);

                           [0, 0, 0, 0, 0]

Yes, often pdsolve gives a symbolic answer only without boundary conditions and/or initial conditions, like

pdsolve(PDE,build);

in the original example.

Alec

PS Not related to that, I'm just curious, whether your favorite mathematician was born in 1856, or in 1903? -Alec

You can check your answer for the original problem in Maple,

pdetest(u(x,t)=(l/Pi)^2*sin(Pi*x/l)*(1-exp(-t/2)*
(cos(sqrt(Pi^2/l^2-1/4)*t)+1/2/sqrt(Pi^2/l^2-1/4)*
sin(sqrt(Pi^2/l^2-1/4)*t))), [PDE,BCs,ICs]);

                           [0, 0, 0, 0, 0]

Yes, often pdsolve gives a symbolic answer only without boundary conditions and/or initial conditions, like

pdsolve(PDE,build);

in the original example.

Alec

PS Not related to that, I'm just curious, whether your favorite mathematician was born in 1856, or in 1903? -Alec

I think, you are doing everything correct - it's just Maple is uncapable to solve this PDE with given BCs and ICs. 

Alec

I think, you are doing everything correct - it's just Maple is uncapable to solve this PDE with given BCs and ICs. 

Alec

The main useful application would be saving Maple sessions - i.e. saving all the variables and their values (including huge arrays) in an h5 file.

Alec

Is there such a grade as an F in your school? 

Alec

Is there such a grade as an F in your school? 

Alec

For B, I posted the code just above. Here is the code for C,

c:=[seq((-1)^n*(n^2+n-1)/(3*n^2+n),n=1..100)]:
plot([$1..100],ListTools:-PartialSums(c));

Alec

For B, I posted the code just above. Here is the code for C,

c:=[seq((-1)^n*(n^2+n-1)/(3*n^2+n),n=1..100)]:
plot([$1..100],ListTools:-PartialSums(c));

Alec

The first example can be also done as 

w[..,[3,4]];

                   [[3, 4], [5, 6], [7, 8], [4, 5]]

or with 1..-1 instead of .. in earlier Maple versions.

The second example can be done straightforward as

map(p->[-p[1],p[2]],b);

  [[-1, 2], [-3, 4], [-5, 6], [-7, 8], [-9, 8], [-7, 6], [-5, 4],

        [-3, 2]]

or as

map[3](applyop,`-`,1,b);

  [[-1, 2], [-3, 4], [-5, 6], [-7, 8], [-9, 8], [-7, 6], [-5, 4],

        [-3, 2]]

Alec

The first example can be also done as 

w[..,[3,4]];

                   [[3, 4], [5, 6], [7, 8], [4, 5]]

or with 1..-1 instead of .. in earlier Maple versions.

The second example can be done straightforward as

map(p->[-p[1],p[2]],b);

  [[-1, 2], [-3, 4], [-5, 6], [-7, 8], [-9, 8], [-7, 6], [-5, 4],

        [-3, 2]]

or as

map[3](applyop,`-`,1,b);

  [[-1, 2], [-3, 4], [-5, 6], [-7, 8], [-9, 8], [-7, 6], [-5, 4],

        [-3, 2]]

Alec

For plots, undefined would produce the same effect - it is not plotted.

Also, it could be used for min and max, as

min[defined](1,undefined);
                                  1

Alec

For plots, undefined would produce the same effect - it is not plotted.

Also, it could be used for min and max, as

min[defined](1,undefined);
                                  1

Alec