ArcCos[]
- To: mathgroup at smc.vnet.net
- Subject: [mg24730] ArcCos[]
- From: Gianluca Gorni <gorni at dimi.uniud.it>
- Date: Wed, 9 Aug 2000 02:31:30 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hello!
I have just come across one more example that shows how there is
room for improving Mathematica's trig functions.
With Mathematica 4:
v = Cos[ Pi/8 ] // FunctionExpand gives Sqrt[2 + Sqrt[2]]/2
Still, neither
ArcCos[v] // FunctionExpand nor ArcCos[v] // FullSimplify
give Pi/8, as I would expect, but just
ArcSec[2/Sqrt[2 + Sqrt[2]]]
%%%%%%%%%%%%%%%
An unrelated problem: the following instructions consistently crash
my Mac Mathematica 4 kernel:
a = Root[-t + 2*#1 + 2*t^2*#1 + #1^3 & , 1];
b = D[a, t];
Solve[b == 0, t]
%%%%%%%%%%%%%%%
Best regards,
Gianluca Gorni
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| Gianluca Gorni |
| Universita` di Udine |
| Dipartimento di Matematica |
| e Informatica |
| via delle Scienze 208 |
| I-33100 Udine UD |
| Italy |
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