Example 2.5.5 There are 6 different elements of class A and 4 different elements of class B. In a certain experiment, an even number of elements from class A must be taken, and no fewer than 2 elements from class B must be taken. How many experimental schemes are there?
$$
\begin{aligned}
f(x) & =\left(1+\mathrm{C}_{6}^{2} x^{2}+\mathrm{C}_{6}^{4} x^{4}+\mathrm{C}_{6}^{6} x^{6}\right)\left(\mathrm{C}_{4}^{2} x^{2}+\mathrm{C}_{4}^{3} x^{3}+\mathrm{C}_{4}^{4} x^{4}\right) \\
& =\left(1+15 x^{2}+15 x^{4}+x^{6}\right)\left(6 x^{2}+4 x^{3}+x^{4}\right),
\end{aligned}
$$

All experimental schemes are $\sum_{k=2}^{10} f_{k}=f(1)=32 \times 11=352$.
