based on the completeness of the
functions 
in one dimension using the following procedure:
in one dimension to
expand a general function of two variables
in terms of the 
and a set of functions 
of y,
Explain briefly why the completeness of the 
allows you
to do this. Give an expression for the functions
in terms of an integral involving 
and 
.
,
Explain briefly why the completeness of the 
allows you
to do this. Give an expression for the constants
in terms of an integral involving the 
and the
.
into your
original expansion (2) to show as required that any
function 
may be written
Also, show that the expansion coefficients 
you
derived in the previous step are precisely the same as those you wrote
down in e).
