[!info] Echelon Form
pivot（主元）: The first non-zero entry of a row
- 全零行一定在最后
- 下面的pivot一定在上面的pivot右边
- pivot下面都是0
!454x177[!NOTE] Reduced Echelon Form
• 每个pivot都是1
• 每个pivot都是一列中唯一的非零数字
!483x172[!tip]
Each Matrix is row equivalent to one and only one reduced echelon matrix