@janhardo As seen, Maple knows the symbolic value of Zeta(2).
It is possible to deduce it e.g. from the infinite product expansion of sin(x) (see below), but it would be much more useful for you to read a few known mathematical proofs in the given references.

Download zeta2.mw

@janhardo Euler product formula can be written in Maple this way:

but note that Maple cannot use ithprime symbolically.

@Jesús Guillera You have to be careful because e.g.  1 + 4 + 4^2 + ...  = -1/3.
Also, F(z) converges only for |z| < 1 and for some points with |z|=1.

@NIMA112  y[2] still present! Check with indets

lprint(indets(zz, name));

# {Delta, Q__01, Q__02, T__1, T__2, a, alpha, b, beta, lambda, v, x, x__01, x__02, y, y__01, y__02, y[2]}

@NIMA112 Of course it does not work because you also have y[2].

@sand15 Yes, but try to compare the timings for e.g.

d := rand(10^20 .. 10^30)():
n := d^rand(100 .. 1000)()*rand(10^10..10^20)():

@nm Try  n:=90; d:=3;

@dharr Just a remark. The eigenvalues are not correctly sorted; the option key=evalf should be added.

@mehdi jafari 
 

@acer However,

restart;
local a; 	
a := 17:
:-a := 18:
p := proc()
  local a;
  a := 25;
  return parse("a",statement);
end proc:

p();  #17

@mmcdara Sorry, probably I have seen an older version of your answer, or maybe I was not careful enough.

@mmcdara You have ommited useassumptions. So, solve has another task: a single inequality instead of a system.

@Axel Vogt Just replace 10.0 by 10

@sursumCorda 
I used Maple 2018 on an old Windows tablet  and I obtain 
limit(1/f, x=infinity) = 0.

@petit loup   "#" starts a comment, so actually method='integer'  is not needed when the matrix has integer entries.
For our matrix A,
S,U,V := SmithForm(A, output=['S,U,V'], method='integer');
and
S,U,V := SmithForm(A, output=['S,U,V']);
give the same result.