Definition
In the context of calculus, finite sums (Riemann sums) are used to estimate the total distance a body travels by slicing its path into infinitesimally small time intervals and summing the distance covered in each.
Why It Matters
Static measurements are insufficient for systems in motion. Without these approximations, an autonomous vehicle couldn’t calculate its battery range or predict its arrival time, as velocity is never a constant. This provides the grounding needed for high-stakes navigation and path monitoring.
Core Concepts
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Distance Traveled Approximation: If is a velocity function, the distance traveled over can be estimated by summing distances over small time intervals :
- How to read: “The distance D is approximately equal to the sum from k equals one to n of the absolute value of v of t k, multiplied by delta t.”
- Meaning: Add up (speed) × (small time slice)—Riemann sum for total path length regardless of direction changes.
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Distance vs. Displacement: Summing the velocity directly () yields the displacement (net change in position), while summing the speed () yields the total distance traveled.
- How to read: “The term v of t k times delta t represents displacement, while the absolute value of v of t k times delta t represents distance.”
- Meaning: Signed velocity can cancel on round trips; speed (absolute value of velocity) always adds positive contributions.