Changes

*The Permutation is denoted by <math> _nP_k, P_{n,k}, or P(n,k) </math>.This function will give the result as error when  

*The Permutation is denoted by <math> _nP_k, P_{n,k}, or P(n,k) </math>.This function will give the result as error when  

  1.n and nc are nonnumeric.

  1.n and nc are nonnumeric.

  2.Suppose <math> n\le 0 or nc<0 or n<nc</math>.

  2.Suppose <math> n \le 0   or   nc < 0 or n < nc </math>.

==Examples==

==Examples==