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which u/v interval was used to create these famous surfase? --RokerHRO (talk ) 10:11, 6 August 2010 (UTC) [ reply ]
Starting with the equations for the Enneper surface,
x
=
u
(
1
−
u
2
/
3
+
v
2
)
/
3
,
y
=
v
(
1
−
v
2
/
3
+
u
2
)
/
3
,
z
=
(
u
2
−
v
2
)
/
3
{\displaystyle x=u(1-u^{2}/3+v^{2})/3,y=v(1-v^{2}/3+u^{2})/3,z=(u^{2}-v^{2})/3}
,
we can eliminate
u
{\displaystyle u}
and
v
{\displaystyle v}
to produce the degree 9 polynomial
64
z
9
−
128
z
7
+
64
z
5
−
702
x
2
y
2
z
3
−
18
x
2
y
2
z
+
144
(
y
2
z
6
−
x
2
z
6
)
{\displaystyle 64z^{9}-128z^{7}+64z^{5}-702x^{2}y^{2}z^{3}-18x^{2}y^{2}z+144(y^{2}z^{6}-x^{2}z^{6})\ }
+
162
(
y
4
z
2
−
x
4
z
2
)
+
27
(
y
6
−
x
6
)
+
9
(
x
4
z
+
y
4
z
)
+
48
(
x
2
z
3
+
y
2
z
3
)
{\displaystyle {}+162(y^{4}z^{2}-x^{4}z^{2})+27(y^{6}-x^{6})+9(x^{4}z+y^{4}z)+48(x^{2}z^{3}+y^{2}z^{3})\ }
−
432
(
x
2
z
5
+
y
2
z
5
)
+
81
(
x
4
y
2
−
x
2
y
4
)
+
240
(
y
2
z
4
−
x
2
z
4
)
−
135
(
x
4
z
3
+
y
4
z
3
)
=
0.
{\displaystyle {}-432(x^{2}z^{5}+y^{2}z^{5})+81(x^{4}y^{2}-x^{2}y^{4})+240(y^{2}z^{4}-x^{2}z^{4})-135(x^{4}z^{3}+y^{4}z^{3})=0.\ }
.
For example, in Wolfram Mathematica or (free, on-line) Wolfram Alpha ,
Eliminate[{x == u*(1 - u^2/3 + v^2)/3, y == v*(1 - v^2/3 + u^2)/3, z == (u^2 - v^2)/3}, {u, v}]
produces an equation of the form
p
(
x
,
y
,
z
)
=
q
(
x
,
y
,
z
)
{\displaystyle p(x,y,z)=q(x,y,z)}
where
p
(
x
,
y
,
z
)
−
q
(
x
,
y
,
z
)
=
0
{\displaystyle p(x,y,z)-q(x,y,z)=0}
is the above degree 9 polynomial.
MathPerson (talk ) 15:37, 21 April 2021 (UTC) [ reply ]