Equation 2 · AI Inference Economics in Practice: An Advanced Technical Guide
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Symbol r
r is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
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What the article says around this equation
That convergence on roughly one tenth of base input for a cache read — independently verified today across all three platforms [ 2 , 6 , 10 ] — supports a design rule. Let w be the write-price multiplier for the chosen retention window and r 0.1 the read-price multiplier. For a prefix served identically R times within that window — the first serving is the write, the remaining R-1 are reads — caching beats never caching once
Sources cited in the article section
- [5] Prompt Caching ↗
- [2] Prompt Caching ↗
- [9] Context Caching ↗
- [6] Pricing ↗
- [10] Gemini Developer API Pricing ↗
These citations give research context. Read each source to check which claims it supports.
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