Axel Vogt

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17 years, 190 days
Munich, Germany

MaplePrimes Activity

These are questions asked by Axel Vogt

The question disappeared (I know since I answered today).


Loading a package and using a member with single quotes leads Maple to display the package name, for example

Int(f(x), x):

'Change(%, x=1/t, t)'; 
          IntegrationTools:-Change( |  f(x) dx, x = 1/t, t)

Is there an easy way to avoid the display of the package name in such a command?

Moreover I sometimes use eval(foo) to display a (former) definition of a function foo and then also the package name is printed (which I do not always want to see) if it was used in the definition.

Compare seq(-GAMMA(k+1, x), k = 0 .. -2) and seq(-GAMMA(k+1, x), k = -2 .. 0)

sum(-GAMMA(k+1, x), k = -2 .. 0) = -1/x*Ei(2,x)-Ei(1,x)-exp(-x) may be what you expect

Int(exp(t), t= 0 ..x) +1 is just a way to write exp(x), use value(%).

ff:= x -> evalf(Int(exp(t), t= 0 .. x, method = _d01ajc) + 1) does
the same, but in a numerical way.

Now consider that as a differential equation, to be solved numerically:

de:=D(f)(x) = f(x);
dsolve({%, f(0)=1});
                         f(x) = exp(x)

ff:= x -> evalf(Int(exp(t), t= 0 .. x, method = _d01ajc) + 1);

D(f)(x) = ff(x);
sol:=dsolve({%, f(0)=1}, numeric);

  Warning, The use of global variables in numerical ODE problems is deprecated,
  and will be removed in a future release. Use the 'parameters' argument instead
  (see ?dsolve,numeric,parameters)


  Error, (in sol) parameter 't' must be assigned a numeric value before
  obtaining a solution

Question: how to write it down correctly?

g := (-12*y^2+1)/(4*y^2+1)^3 * ln(abs(-1+2^(1-x-I*y)));

Compute Int(g, [x=1/2 .. infinity, y=0 .. infinity]).

PS: this stems from How to calculate hard integral?,
but it is not related to the RH.
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