∫
−
∞
∞
e
−
x
2
d
x
=
π
\int_{-\infty}^{\infty} e^{-x^2}\,dx = \sqrt{\pi}
P
(
A
∣
B
)
=
P
(
B
∣
A
)
P
(
A
)
P
(
B
)
P(A \mid B) = \frac{P(B \mid A)\,P(A)}{P(B)}
(2)
A right triangle keeps
a
2
+
b
2
=
c
2
a^2 + b^2 = c^2
on one line.