Advanced Topic 44 of 51 Math for Computing
Interpolation
Estimating values between known points.
How it works
Interpolation constructs a function that passes exactly through a given set of data points, to estimate values in between. Methods include linear interpolation between neighbors, polynomial interpolation using Lagrange or Newton forms, piecewise approaches such as cubic splines that ensure smoothness of the first and second derivatives, and Hermite interpolation that matches slopes. Related ideas are extrapolation beyond the data and approximation, such as least squares, which need not hit all points.
Where it is used
Resampling images and audio, plotting smooth curves from samples, lookup tables in embedded systems, animation keyframes, terrain heights and filling gaps in time series use interpolation.
Common pitfall
High-degree polynomial interpolation on evenly spaced points oscillates wildly near the ends, Runge's phenomenon; use splines or Chebyshev nodes. Extrapolation is unreliable. Noisy data should be smoothed or fitted, not interpolated exactly. Monotonicity and positivity may not be preserved by splines, so use shape-preserving variants when needed.
Where it fits in the course
Interpolation is topic 44 of 51 in Math for Computing, rated Advanced. It follows Numerical Integration. The next topic is Markov Chains.
Practice and explore
- Open the interactive lesson, with a mini quiz.
- Take the Math for Computing quiz.
How to study this topic
- Read the explanation above and restate the definition in your own words.
- Open the interactive lesson and answer its mini quiz.
- Read the common pitfall, then write a short example that avoids it.
- Check your understanding in the Math for Computing quiz, and revisit the topic if you miss a question.
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Related topics
- Numerical Integration (Math for Computing)
- Markov Chains (Math for Computing)
- Root Finding (Math for Computing)
- Monte Carlo Methods (Math for Computing)