Axel Vogt

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15 years, 261 days
Munich, Germany

MaplePrimes Activity


These are questions asked by Axel Vogt

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)

sol(1);

  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

I installed M16 32 Bit on my new machine with Win7 64 Bit.

But the following results in crushing mserver.exe:

  tmp := proc( x :: float ) :: float; 2.3 * x end proc:
  cp:=Compiler:-Compile(tmp);

with system info below.

Do I have to set certain rights for the compiler or define a specific working directory?

The FAQ http://www.maplesoft.com/support/faqs/results.aspx?search=compiler does not help me.

Dito http://www.maplesoft...
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