Show that the term containing x3 does not exist in the expansion of .
For ,
a=3x, and n=8
We have a formula,
To get coefficient of x3 we must have,
(x)8-2r = (x)3
• 8 - 2r = 3
• 2r = 5
• r = 2.5
As is not possible
Therefore, the term containing x3 does not exist in the expansion of