Solución
a.
M
x
=
0
,
M
y
=
0
M_x = 0, M_y = 0
M
x
=
0
,
M
y
=
0
b.
x
ˉ
=
0
,
y
ˉ
=
0
\bar{x} = 0, \bar{y} = 0
x
ˉ
=
0
,
y
ˉ
=
0
