WEBVTT

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A constant should have zero derivative.

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At x = 0: NaN derivative instead of 0.

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Higher derivatives of integer powers also fail.

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1 + 2x + 3x²: NaN first gradient instead of 2.

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Direct polynomial and finite differences give 2.

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Synthetic loss: 4.5 → NaN before; 0.017578125 after.

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The derivative computes 0 × Inf.

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Narrow guard: real zero base AND zero exponent.

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Local C++ patch: 41 scenarios, 396 checks pass.

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A duplicate method name hides older power tests.

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Known error family. Local CPU, partial rebuild.

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Full-model impact and novelty unestablished.