Question

In the expansion of (e x-1-x)/x 2 in ascending powers of x ,the 4 th​ term is

Answer 1

ex−1−xx2=(1+x+x22!+x33!+x44!+x55!+...)−1−xx2=(x22!+x33!+x44!+x55!+...)x2=1x2(x22!+x33!+x44!+x55!+...)=(12!+x3!+x24!+x35!+...)Thus, 4th term is x35!.