Tech article
A Number with a Shadow
Community description: 3 points · 0 comments on Hacker News
Hacker News | Mar 5, 2026 | davedx
Automated excerpt
At tiny h, f(x + h) and f(x) are nearly identical in floating point. Seed x = (3, 1), value 3, derivative 1 because ∂x/∂x = 1. Type an expression and watch the dual numbers propagate through every operation.
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