Matrix Multiplication
Multiply the two matrices shown:
Expand Hint
Matrix A is a 3-row, 2-column matrix. Matrix B is a 2-row, 2-column matrix. For multiplication to be possible, the number of columns in A must equal the number of rows in B.
Hint 2
Multiplying matrix B by matrix A:
$$$C=\begin{bmatrix}a & b\\ c & d\\ e & f\end{bmatrix}\cdot \begin{bmatrix}h & i\\ j & k\end{bmatrix}=\begin{bmatrix}(a\cdot h+b\cdot j) & (a\cdot i+b\cdot k)\\ (c\cdot h+d\cdot j) & (c\cdot i+d\cdot k)\\ (e\cdot h+f\cdot j) & (e\cdot i+f\cdot k)\end{bmatrix}$$$
Matrix A is a 3-row, 2-column matrix. Matrix B is a 2-row, 2-column matrix. For multiplication to be possible, the number of columns in A must equal the number of rows in B. Multiplying matrix B by matrix A:
$$$C=\begin{bmatrix}a & b\\ c & d\\ e & f\end{bmatrix}\cdot \begin{bmatrix}h & i\\ j & k\end{bmatrix}=\begin{bmatrix}(a\cdot h+b\cdot j) & (a\cdot i+b\cdot k)\\ (c\cdot h+d\cdot j) & (c\cdot i+d\cdot k)\\ (e\cdot h+f\cdot j) & (e\cdot i+f\cdot k)\end{bmatrix}$$$
Thus,
$$$\begin{bmatrix}1 & 2\\ 3 & 4\\ 5 & 6\end{bmatrix}\cdot \begin{bmatrix}7 & 8\\ 9 & 10\end{bmatrix}=\begin{bmatrix}(1\cdot 7+2\cdot 9) & (1\cdot 8+2\cdot 10)\\ (3\cdot 7+4\cdot 9) & (3\cdot 8+4\cdot 10)\\ (5\cdot 7+6\cdot 9) & (5\cdot 8+6\cdot 10)\end{bmatrix}$$$
$$$=\begin{bmatrix}(7+18) & (8+20)\\ (21+36) & (24+40)\\ (35+54) & (40+60)\end{bmatrix}=\begin{bmatrix}25 & 28\\ 57 & 64\\ 89 & 100\end{bmatrix}$$$
$$$\begin{bmatrix}25 & 28\\ 57 & 64\\ 89 & 100\end{bmatrix}$$$
Time Analysis
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