nCr/nPr=r!give proof.
That's not true. If \(n\mathrm Cr\) and \(n\mathrm Pr\) are defined as\(n\mathrm Cr=\dfrac{n!}{r!(n-r)!}\)\(n\mathrm Pr=\dfrac{n!}{(n-r)!}\)then\(\dfrac{n\mathrm Cr}{n\mathrm Pr}=\dfrac{\frac{n!}{r!(n-r)!}}{\frac{n!}{(n-r)!}}=\dfrac1{r!}\)
