onegirl Group Title Write 3 + 5 + 7 + 9 + 11 + 13 + 15 in sigma notation. one year ago one year ago

1. ParthKohli Group Title

$= [2(1) + 1] + [2(2) + 1] \cdots [2(7) + 1]$

2. JoãoVitorMC Group Title

$\sum_{n=1}^{7} 2n + 1$

3. onegirl Group Title

okay