What is the area of a parallelogram spanned by vectors a = 3i + j and b = i + 4j?
Answer and explanation
Correct answer: C. 11 square units
- Step 1: Area is magnitude of cross product |a x b|. Step 2. a x b = (3 4 - 1 1) k = (12 - 1) k = 11 k. Step 3. Magnitude = |11 k| = 11. Answer: 11 square units. Why not the others: 7 is 3+4; 13 is sqrt(3^2+4^2+...).
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