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Inverse cosine rationalization omits the x plus one factor · case 02

Inverse cosine rationalization omits the x plus one factor.

Member previewVariant 2 · 3 implementations · 8 checks per implementation

Case contract

Evaluate inverse hyperbolic cosine for finite x>=1. Use logarithmic scaling for huge inputs and a log1p expression near one. Finite results are rendered to eleven significant decimal digits; modeled domain violations and arithmetic errors are explicit strings.

Why this case matters

An offline floating representation model isolates a reproducible arithmetic fault.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
fixed near one	`"1.7763568394e-15"`	`"4.2146848511e-08"`	Failed

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