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Mathematics
Mathematics
Problem
Let
f
(
x
)
=
α
x
x
+
1
f(x) = \frac{\alpha x}{x+1}
f
(
x
)
=
x
+
1
α
x
,
x
≠
−
1
x \neq -1
x
=
−
1
. Then, for what value of
α
\alpha
α
is
f
[
f
(
x
)
]
=
x
f[f(x)] = x
f
[
f
(
x
)]
=
x
? a.
2
\sqrt{2}
2
b.
−
2
-\sqrt{2}
−
2
c. 1 d.
−
1
-1
−
1
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