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Mathematics
Mathematics
Problem
The range of the signum function
sgn
(
x
)
\operatorname{sgn}(x)
sgn
(
x
)
defined for all real
x
x
x
is a)
[
−
1
,
1
]
[-1,1]
[
−
1
,
1
]
b)
{
−
1
,
0
,
1
}
\{-1,0,1\}
{
−
1
,
0
,
1
}
c)
{
−
1
,
1
}
\{-1,1\}
{
−
1
,
1
}
d)
[
0
,
∞
)
[0,\infty)
[
0
,
∞
)
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