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Swedish Mathematical Competition
1980 Swedish Mathematical Competition
4
4
Part of
1980 Swedish Mathematical Competition
Problems
(1)
int f(x)g(x) dx <= int f(x)g(1-x) dx
Source: 1980 Swedish Mathematical Competition p4
3/28/2021
The functions
f
f
f
and
g
g
g
are positive and continuous.
f
f
f
is increasing and
g
g
g
is decreasing. Show that
∫
0
1
f
(
x
)
g
(
x
)
d
x
≤
∫
0
1
f
(
x
)
g
(
1
−
x
)
d
x
\int\limits_0^1 f(x)g(x) dx \leq \int\limits_0^1 f(x)g(1-x) dx
0
∫
1
f
(
x
)
g
(
x
)
d
x
≤
0
∫
1
f
(
x
)
g
(
1
−
x
)
d
x
integration
analysis
inequalities