26.17.2 Envelopes
The
envelope
command draws the envelope of a family of curves.
envelope
takes two arguments:
expr
, an expression of two variables and one parameter.
L
, a list of the names of the variables and the parameter. If the variables are
x
and
y
, then
L
only need to be the name of the parameter.
envelope(
expr
,
L
)
draws the envelope of the family of curves given by
expr
=0.
Example
envelope
(
y
+
x
*
tan
(
t
)-2*
sin
(
t
),
t
)
or:
envelope
(
v
+
u
*
tan
(
s
)-2*
sin
(
s
),[
u
,
v
,
s
])
