Exercise 12

Use summation ($\sum$) or product ($\prod$) notation to rewrite the following.

1. $2 + 4 + 6 + 8 + \cdots + 2n$.
2. $1 + 5 + 9 + 13 + \cdots + 425$.
3. $1 + \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + \cdots + \frac{1}{50}$.
4. $2 \cdot 4 \cdot 6 \cdot \cdots \cdot 2n$.
5. $(\frac{1}{2})(\frac{2}{3})(\frac{3}{4})\cdots(\frac{100}{101})$.