Find the dot product of the vectors a = (2, 7) and b = (-1, -3).
Answer and explanation
Correct answer: B. -23
- Step 1: The dot product is a.b = x1 x2 + y1 y2.
- Step 2: a.b = (2)(-1) + (7)(-3) = -23.
Answer
-23.
Why not the others: '-13' cross-multiplies the components; '19' subtracts the second product; '1' gives the 2D cross product.
Practise more Algebra, Functions, Geometry and Probability.
Free questions with an explanation for every one, and full timed Državna Matura (Bosnia & Herzegovina) mock tests.