We like to write equations and formulas which can be read by others:
A
=
±
ó
õ
b
a
f(x) dx
=
ì
ï
í
ï
î
ó
õ
b
a
f
(
x
)
dx
,
f
(
x
)
³
0
,
-
ó
õ
b
a
f
(
x
)
dx
,
f
(
x
)
£
0
.
File translated from T
E
X by
T
T
H
, version 3.77.
On 21 Dec 2006, 09:09.