Finding the Coefficient of a Power of x in the Binomial Expansion
In the binomial expansion of
the coefficient of
is
This is the (r+1) th term in the binomial expansion ofin ascending powers of
Suppose that a=2 and b=3x^2 . To find the coefficient of
in the binomial expansion of
put
then the coefficient of
is
and the coefficient ofis
If both a and b are terms in x then things get slightly more complicated.
Suppose we want to find the coefficient ofin the binomial expansion of
and
so the coefficient of
is
and the (r+1) th term is
Put
thenso the coeeficient ofis