Lines & Closest Approach

Moving points as vectors

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Vector line: $\mathbf r(t) = \mathbf a + t\mathbf d$.
• Closest approach: minimise the length of the separation vector.
• Intersections: set components equal and solve for both parameters.

Steps

1. A line as a journey
2. Where after 2 hours?
3. Closest approach
4. How close?
5. The same line?
6. Where do they cross?