Question

Hello guys
please solve this​

Answer 1

$Given: \frac{1}{1!(n-1)!} + \frac{1}{3!(n-3)!} + \frac{1}{5!(n-5)!}$

It can be written as,

$=> \frac{1}{n!} [\frac{n!}{1!(n-1)!} + \frac{n!}{3!(n-3)!} + \frac{n!}{5!(n-5)! + ..... }]$

$=> \frac{1}{n!} [C(n,1) + C(n,3) + C(n,5) + ....... ]$

$=> \frac{1}{n!} * 2^{n - 1}$

$=> \boxed {\frac{2^{n - 1}}{n!}}$

Hope this helps!

Answer 2

Hey hey!

Refer the pic above!