Mathematics · important
Boundary values of permutations for JEE
Meaning of P(n,r) and C(n,r)
Formula
\(\,{}^nP_0=1,\quad {}^nP_1=n\)
Variables: \(n\) is a non-negative integer.
Conditions: Valid for non-negative integer \(n\).
Edge cases in counting and recurrence simplification.