• find the coefficient of x40 in the expansion of (1/x2 + x4)18
  • find 1st 4 terms in the expansion of ( 1 –x )-1/4
  • show that there is no constant in the exoansion of (2x – x2/4)9
  • using binomial theorem find the value of (9.9)3

find the coefficient of x40 in the expansion of (1/x2 + x4)18


 Let (r + 1)th term contains x40 in the binomial expansion of 



For the coefficient of  x40 ,


⇒6r = 40+36=76

 r = 38/3, 

which is impossible.

Thus, there is no term involving x40 in  .

Find the value of (9.9)3


Show that there is no constant in the expansion of



By using general term of the binomial theorem, 

Now, the exponent of x = 0

Thus, there is no constant in the given expansion as the r has negative value

  • -1
What are you looking for?