The result of multiplying a matrix by some vector:
is a combination of the columns of the matrix
example:
1
for each column like this:
右乘列向量代表各列加權求和,最終結果是一列
for each row like this:
左乘一個行向量代表各行加權求和,其最終結果是一個行向量
兩矩陣相乘:
AB = sum(cols of A) *(rows of B)
判斷矩陣A是否可逆:
if AX = 0 and to any X != 0:
A inverse is existed
求解矩陣的逆
Giauss - Jordan