       something (not) funny!

• To: mathgroup at smc.vnet.net
• Subject: [mg79978] something (not) funny!
• From: dimitris <dimmechan at yahoo.com>
• Date: Fri, 10 Aug 2007 01:42:23 -0400 (EDT)

```CAS (Mathematica 5.2 in particular) can be funny sometimes!

[Seriously now, I understand the difficulties and the problems
that appeared possibly in the following examples and more or less
I can figure what goes wrong.

Note that one of this examples appeared in a recent post

That's why we should trust but verify results from CASs...

Anyway, since for someone-not me!- it is vacation period
it is needed some fun!]

Version->5.2

Example 1

In:=
Timing[FourierTransform[Sech[x*a], x, s]]

Out=
{58.359*Second, (Sqrt[Pi/2]*Sech[(Pi*s)/(2*a)])/a}

However,

In:=
TimeConstrained[FourierTransform[Sech[x*Log], x, s], 300]

Out=
\$Aborted

Example 2

In:=
TrigToExp[Sech[x*a]]
FourierTransform[%, x, s]

Out=
2/(E^((-a)*x) + E^(a*x))

Out=
(Sqrt[Pi/2]*Sech[(Pi*s)/(2*a)])/a

In:=
TrigToExp[Sech[x*Log]]
FourierTransform[%, x, s]

Out=
2/(2^(-x) + 2^x)

Out=
FourierTransform[2/(2^(-x) + 2^x), x, s]

Dimitris

```

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