- 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
SOLUTION:
Let (r + 1)th term contains x40 in the binomial expansion of
Now,
For the coefficient of x40 ,
-36+6r=40
⇒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
SOLUTION:
Show that there is no constant in the expansion of
SOLUTION:
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