## 5662 Reputation

18 years, 194 days
Munich, Bavaria, Germany

## Application Center: why mw-files only?...

There is a very nice sheet by Sergej Moiseev Orthogonal Functions, Orthogonal Polynomials, and Orthogonal Wavelets series expansions of function at the Application Center, www.maplesoft.com/applications/app_center_view.aspx.

## problem with an exponential integral - b...

Maple
```Int(exp(-1/100+1/1000*I*u)/(4*u^2+1)*exp(1/2*I*u),u = 0 .. 1)

The integrand has positive real and imaginary parts over the
range (just use plot it) and numerical evaluation gives it as
0.53434219089626 + 0.98249392969436e-1 * I (using Digits:=14).

A symbolic integration and using evalf gives the same.

Now writes this as

tstData:=[a=0, b=1, m=1/2, b0 = -1/100, b1 = 1/1000];

J:=Int(exp(b0+b1*u*I)/(4*u^2+1)*exp(u*m*I),u = a .. b);
eval(J,tstData...```

## looking for a continous anti-derivate fo...

Maple
```I want a continous anti-derivate (cos(2*u*m)-alpha*u*sin(2*u*m))/(4*u^2+1)
w.r.t. u, for alpha and m Reals, 0 < u.

What I get with Maple in terms of Ci and Si jumps in m=0 (and for m=0 it
is not defined, due to Ci).

The best I got was

Si(-conjugate(v))-Si(v); eval(%, v=m*(2*u+I));
psi:= unapply(%, u,m);
chi:= (u,m) -> piecewise(0 <= m, -Ci((2*u-I)*m)+Ci(m*(2*u+I)),
```

## discrete cosine / sine transform...

Maple

I wanted to use (one of the variouos) cosine transforms DCT, but only find FFT in Maple12.

Googling did not give me more (except there seem to recipes to reduce my theme in some
brute (?) ways to a FFT problem).

Is there any Maple solution around (even if I can use Clenshaw's algorithm having only a
moderate size - but want to see some generalisation ...)?

## trouble with MultiSeries: series resp as...

Maple
```I want the asymptotics for EllipticF(z,k) w.r.t. z (yes, not k).

My example is F:=I*EllipticF(c*I/x,k), c=2-2^(1/2),k=3+2*2^(1/2)
and I want the limit x ---> 0+.

MultiSeries:-limit(E,x=0);

results in 0.54... + 0.54...*I (real = imag, positive value).

MultiSeries:-series(E,x,3);

gives (after clearing the output) the same for setting x=0.

For Numerics my setting is Digits:=24 and eps:=1/10^18.

subs(c=2-2^(1/2), k=3+2*2^(1/2), F...```
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