Question

From Question 10c, What is DC_{3,1}DC
3,1
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Answer 1

DC₃₁ is the entry of the product DC in row 3, column 1, which you get by computing the dot product of the 3rd row of D and the 1st column of C :

{3, -2} • {1, 4} = 3×1 + (-2)×4 = 3 - 8 = -5