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
and
To find the coefficient of
in the binomial expansion of
put
then the coefficient of
is
and the coefficient ofis
If both
and
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