Solution
= Solution
Multiply the two <power series> and collect equal powers of $x$. The <Cauchy product> gives
$$
\boxed{c_0=a_0b_0,\qquad c_1=a_0b_1+a_1b_0,\qquad c_2=a_0b_2+a_1b_1+a_2b_0.}
$$
Only terms whose two exponents add to the target exponent contribute.