if f(n)=

   where a1, a2, a3...., an are constants

then f(n)=?

(ans)=a1a2a3.........an

it is of the form 1^infinity

so

= e^lim[ (a1)^1/x ...................(an)^1\x  ] \n *nx

=e^lna1*lna2..........lnan

=a1a2a3.....an