McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
7. Vectors
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Exercise 54 Page 690

Practice makes perfect
a Let's begin with recalling how we should perform vector addition.
⟨ a,b ⟩ + ⟨ c,d ⟩ = ⟨ a+c,b+d ⟩ In our exercise we are given that Sydney parked her car and hiked along two paths described by the vectors ⟨ 2, 3⟩ and ⟨ 5,-1⟩ . To find what vector represents her hike along both paths, we need to add these two vectors.
⟨ 2, 3⟩+⟨ 5,-1⟩

⟨ a,b ⟩ + ⟨ c,d ⟩ = ⟨ a+c,b+d ⟩

⟨ 2+5, 3+(-1)⟩
⟨ 2+5,3-1⟩
⟨ 7,2⟩
Her hike along both paths can be represented by the vector ⟨ 7,2⟩ .
b In this part we are asked to evaluate how far Sydney is from her car. To do this, we need to evaluate the magnitude of a vector we found in the previous part. Having been given the component form of a vector ⟨ x_1,y_1 ⟩, we can find the magnitude by substituting (7, 2) and (0,0) into the Distance Formula.
sqrt((x_2-x_1)^2+(y_2-y_1)^2)
sqrt(( -7)^2+( -2)^2)
Evaluate
sqrt((-7)^2+(-2)^2)
sqrt(7^2+2^2)
sqrt(49+4)
sqrt(53)
7.2801...
≈ 7.3
Sydney is approximately 7.3 miles from her car.