复旦大学：《线性代数 Linear Algebra》课程教学资源（课件讲稿）2.2 矩阵的代数运算

(後只人季 例3设 B=[bb2…b] a, 6, a, b2 AB=/4

例3 设 1 2 m a a A a       =       B b b b = 1 2 n     1 1 1 2 1 2 1 2 2 2 1 2 n n m m m n a b a b a b a b a b a b AB a b a b a b       =      

(後只人季 22 例4设4=010 B=13 L0 102122 AB=01013|= -1×2+0×1+2×0-1×2+0×3+2×1 0×2+1×1+0×00×2+1×3+0×1 l×2+(-1)×1+1×01×2+(-1)×3+1×1 20 3

例4 设 1 0 2 0 1 0 1 1 1 A   −   =       − 2 2 1 3 0 1 B     =       1 0 2 2 2 0 1 0 1 3 1 1 1 0 1 1 2 0 1 2 0 1 2 0 3 2 1 0 2 1 1 0 0 0 2 1 3 0 1 1 2 ( 1) 1 1 0 1 2 ( 1) 3 1 1 2 0 1 3 1 0 AB     −     = =             −   −  +  +  −  +  +     +  +   +  +     + −  +   + −  +    −   =      