Counting and Combinatorics
GRE · Flashcards · Recall
GRE · FLASHCARDS
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QUESTION
Identify the number of ways to choose a nonempty subset from
n
n
n
elements.
QUESTION
What is the symmetry identity for binomial coefficients
(
n
r
)
\binom{n}{r}
(
r
n
)
?
QUESTION
What is the value of
0
!
0!
0
!
?
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ANSWER
0
!
=
1
0!=1
0
!
=
1
. Defined by convention to ensure consistency in formulas like binomial coefficients and permutations for
r
=
0
r=0
r
=
0
.
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