Question
Question: Find the distance between parallel lines $\frac{x}{2} = \frac{y}{-1} = \frac{z}{2}$ and $\frac{x-1}{...
Find the distance between parallel lines 2x=−1y=2z and 2x−1=−1y−1=2z−1
2 units
Solution
Solution Explanation:
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Write the parametric equations:
For Line 1: Let t be a parameter, then
x = 2t, y = –t, z = 2t.
For Line 2: Let s be a parameter, then
x = 1 + 2s, y = 1 – s, z = 1 + 2s. -
Choose one point from each line:
- From Line 1 (for t = 0): A = (0, 0, 0)
- From Line 2 (for s = 0): B = (1, 1, 1) -
The direction vector for both lines is d = (2, –1, 2).
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Calculate the vector AB = B – A = (1, 1, 1).
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Use the formula for the distance between parallel lines:
Distance = |AB × d| / |d|. -
Compute the cross product:
AB × d = (1, 1, 1) × (2, –1, 2)
= ( (1×2 – 1×(–1)), –(1×2 – 1×2), (1×(–1) – 1×2) )
= (2 + 1, –(2 – 2), (–1 – 2))
= (3, 0, –3). -
Its magnitude is |AB × d| = √(3² + 0² + (–3)²) = √(9 + 9) = 3√2.
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Compute |d| = √(2² + (–1)² + 2²) = √(4 + 1 + 4) = 3.
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Therefore, the distance = (3√2) / 3 = √2.