Q.

The term independent of x in the expansion of ((x+1)(x2/3+1x1/3)(x1)(xx1/2))10, x>1, is:         [2025]

1 120  
2 240  
3 210  
4 150  

Ans.

(3)

We have, ((x+1)(x23+1x13)(x1)(xx12))10

=((x13+1)(x+1x))10=(x131x)10

Tr+1=Cr10(x)10r3(1)r(x)r2

Since, the term is independent of x, then 10r3r2=0

  (20 – 2r) – 3r = 0  r = 4.

Hence, the required term is C410(1)4=210.