x
x
x
n
n
n
1
1
1
x
2
x^2
x
2
x
i
x_i
x
i
α
+
β
\alpha + \beta
α
+
β
n
−
1
n-1
n
−
1
R
\mathbb{R}
R
O
(
n
)
\mathcal{O}(n)
O
(
n
)
x
\textbf{x}
x
v
\mathbf{v}
v
a
b
\frac{a}{b}
b
a
n
+
1
2
\frac{n+1}{2}
2
n
+
1
∂
f
∂
x
\frac{\partial f}{\partial x}
∂
x
∂
f
∑
i
=
0
n
x
i
\sum_{i=0}^{n} x_i
∑
i
=
0
n
x
i
∏
k
=
1
n
k
\prod_{k=1}^{n} k
∏
k
=
1
n
k
value =
a
+
b
2
\frac{a+b}{2}
2
a
+
b
O
(
n
log
n
)
O(n \log n)
O
(
n
lo
g
n
)
∑
i
=
1
n
1
i
2
\displaystyle\sum_{i=1}^{n} \frac{1}{i^2}
i
=
1
∑
n
i
2
1
θ
^
=
x
ˉ
±
σ
n
\hat{\theta} = \bar{x} \pm \frac{\sigma}{\sqrt{n}}
θ
^
=
x
ˉ
±
n
σ