Axel Vogt

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16 years, 69 days
Munich, Germany

MaplePrimes Activity

These are questions asked by Axel Vogt

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.

As of today it does no longer properly load using Firefox, but using IE works

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