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2019 BMT Spring
19
19
Part of
2019 BMT Spring
Problems
(1)
2019 BMT Individual 19
Source:
1/9/2022
Let
a
a
a
and
b
b
b
be real numbers such that
max
0
≤
x
≤
1
∣
x
3
−
a
x
−
b
∣
\max_{0\le x\le 1} |x^3 - ax - b|
max
0
≤
x
≤
1
∣
x
3
−
a
x
−
b
∣
is as small as possible. Find
a
+
b
a + b
a
+
b
in simplest radical form. (Hint: If
f
(
x
)
=
x
3
−
c
x
−
d
f(x) = x^3 - cx - d
f
(
x
)
=
x
3
−
c
x
−
d
, then the maximum (or minimum) of
f
(
x
)
f(x)
f
(
x
)
either occurs when
x
=
0
x = 0
x
=
0
and/or
x
=
1
x = 1
x
=
1
and/or when x satisfies
3
x
2
−
c
=
0
3x^2 - c = 0
3
x
2
−
c
=
0
).
algebra