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# Justification using first derivative

AP.CALC: FUN‑4 (EU), FUN‑4.A (LO), FUN‑4.A.10 (EK), FUN‑4.A.11 (EK)

## Problem

The differentiable function f and its derivative f, prime are graphed.
What is an appropriate calculus-based justification for the fact that f has a relative maximum point at x, equals, c?