Mathematics · supplementary
Ratio of consecutive permutations for JEE
Meaning of P(n,r) and C(n,r)
Formula
\(\dfrac{{}^nP_{r+1}}{{}^nP_r}=n-r\)
Variables: \(n\) is fixed, \(r\) varies.
Conditions: \(0\le r\le n-1\).
Recurrence simplification, comparison of successive permutation counts.