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Putnam
2007 Putnam
2
Putnam 2007 B2
Putnam 2007 B2
Source:
December 3, 2007
Putnam
calculus
derivative
integration
symmetry
function
algebra
Problem Statement
Suppose that
f
:
[
0
,
1
]
→
R
f: [0,1]\to\mathbb{R}
f
:
[
0
,
1
]
→
R
has a continuous derivative and that \int_0^1f(x)\,dx\equal{}0. Prove that for every
α
∈
(
0
,
1
)
,
\alpha\in(0,1),
α
∈
(
0
,
1
)
,
∣
∫
0
α
f
(
x
)
d
x
∣
≤
1
8
max
0
≤
x
≤
1
∣
f
′
(
x
)
∣
\left|\int_0^{\alpha}f(x)\,dx\right|\le\frac18\max_{0\le x\le 1}|f'(x)|
∫
0
α
f
(
x
)
d
x
≤
8
1
0
≤
x
≤
1
max
∣
f
′
(
x
)
∣
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