special values of lesser hyperbolic functions

[kcrisman]

Even though Maxima can evaluate sech(0), Sage does this:

sage: cosh(0)
1
sage: sech(0)
sech(0)

It seems reasonable to fix this. Part of this is probably that sech is not a GiNaC function.

Component: symbolics

Keywords: sech, coth, csch

Author: Ralf Stephan

Branch/Commit: e064ff3

Reviewer: Frédéric Chapoton

Issue created by migration from https://trac.sagemath.org/ticket/10074

[benjaminfjones]

comment:1

Is there a way of initializing a Ginac / Pynac function using a symbolic expression? It would be nice to be able to initialize sech by calling simply:

GinacExpression.__init__(self, '1/cosh', ... 

And the result would behave just like defining sech(z) = 1/cosh(z) in Sage. Then we'd get (as in sage-5.0.beta9):

sage: sech(z) = 1/cosh(z)
sage: sech(0)
1

Maybe this is naive...

[rwst]

Branch: u/rws/improve_less_used_hyperbolic_functions

[rwst]

Commit: b1833cb

[rwst]

Author: Ralf Stephan

[rwst]

New commits:

b1833cb

10074: special values of coth, sech, csch

[fchapoton]

comment:9

badly formatted doc

[sagetrac-git]

Changed commit from b1833cb to 507dc57

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

507dc57

10074: cosmetics

[fchapoton]

Changed commit from 507dc57 to e064ff3

[fchapoton]

Reviewer: Frédéric Chapoton

[fchapoton]

Changed branch from u/rws/improve_less_used_hyperbolic_functions to public/ticket/10074

[fchapoton]

comment:12

Looks good to me, if you agree with my small changes, you can set that to pos.rev.

---

New commits:

16323a3	Merge branch 'u/rws/improve_less_used_hyperbolic_functions' into 6.5.b6
e064ff3	trac #10074 review commit

[rwst]

comment:13

OK. Thanks.

[vbraun]

Changed branch from public/ticket/10074 to e064ff3