,f g
( , )a b
( )x
( , )a b
,f g D
inf{ ( )
f x
x D
( ) max{ ( ),
x
f x g x
( )}
( )} sup{ ( )} inf{ ( )}
g x
g x
f x
x D
x D
lim(
n
n
2 2
n
1
n
) /
3
n
n
2 2
n
1
n
( )
f x
x
ln
x
( )( )
nf
x
a
0,
x
n
n
k
1
sin(
1
2
2
k
n
a
)
nx
a
( )
f x
[0,
)
x
( )
f x
y
,(
ax b a
0)
( )
f x
[0,
)
( )
f x
R
( )
f x
[ , ]a b
( )
F x
x
a
f
( )
t dt x R
,
F
A
0,
f
[0,
]A
0
( )
f x dx
x
0
f
( )
t dt
x
f
( )
,
t dt x
[0,
)
( )
x
(0,
)
( )
f x
[ , ]a b
( , )a b
f
"( )
24
(
b a
3
)
b
a
( )
f x
f
(
a b
2
)
.
dx
n
1
1
0
n
1
( 1)
(
n n
n
1)
.
x
(
n n
n
1)
ln(1
x
)x dx
( )
f x
[0,1]
( )
f x dx
1
n
n
k
1
f
(
k
n
)]
1
2
[
f
(1)
f
(0)].
lim [
n
n
1
0