$\"\"$

The expression is $\"\"$ .

The maclaurin series of $\"\"$ , $\"\"$ and

$\"\"$ , $\"\"$ .

Use multiplication of the power series to find $\"\"$ .

$\"\"$

Four terms are probably enough for product of two polynomials.

$\"\"$

Find first three nonzero terms that is upto $\"\"$ term.

$\"\"$

$\"\"$ .

Product of the two power series upto three nonzero terms is $\"\"$ .

$\"\"$

Product of the two power series upto three nonzero terms is $\"\"$ .