E
=
m
c
2
e
i
π
=
-
1
∀
x
∈
ℂ
(
sin
2
x
+
cos
2
x
=
1
)
∑
i
=
1
n
i
3
=
(
n
(
n
+
1
)
2
)
2
[
a
b
c
d
]
(
1
0
0
1
)
6
<
9