symbolic plotting bug

[kcrisman]

No response on sage-support, so I deem this a bug, not a feature:

sage: plot(sin,0,pi)
<plots fine>
sage: plot(2*sin,0,pi)
<boom>

Although I suppose we should always include variables -

sage: plot(2*sin(x),0,pi)
<plots fine>

- for consistency's (and ease of use's) sake both of the above should
work. 

Component: symbolics

Issue created by migration from https://trac.sagemath.org/ticket/3906

[rlmill]

comment:1

Attachment: trac_3906.patch.gz

This patch is found also at #3907.