Changes

*The construction is related to the binomial coefficients by Pascal's rule is :                                 

*The construction is related to the binomial coefficients by Pascal's rule is :                                 

<math>(x+y)^n=\sum_{k=0}^n \binom{n}{k}x^{n-k} .y^k </math>.    where <math> \dbinom{n}{k}</math> is the binomial coefficient.

<math>(x+y)^n=\sum_{k=0}^n \binom{n}{k}x^{n-k} .y^k </math>.    where <math> \dbinom{n}{k}</math> is the binomial coefficient.

*This function will return the result as error when the <math> r \le 0</math>.

*This function will return the result as error when <math> r \le 0</math>.

==Examples==

==Examples==