Mathematics

Mathematics

Problem

Which of the following statements correctly describes the relationship between continuity and differentiability of a function ff at a point x=cx=c? a) If ff is continuous at cc, then ff must be differentiable at cc. b) If ff is differentiable at cc, then ff must be continuous at cc. c) If ff is not continuous at cc, then ff can still be differentiable at cc. d) Continuity and differentiability are independent; neither property implies the other at cc.
Intuitive explanation

Differentiability is the stronger condition: if a function is differentiable at x=cx=c, it must be continuous there, but continuity alone doesn't guarantee differentiability. The key insight is that differentiability requires a smooth, well-defined slope, while continuity only requires the function to have no jumps or breaks—a function can be continuous but have a sharp corner or cusp where the derivative doesn't exist.

Intuitive explanation

Differentiability is the stronger condition: if a function is differentiable at x=cx=c, it must be continuous there, but continuity alone doesn't guarantee differentiability. The key insight is that differentiability requires a smooth, well-defined slope, while continuity only requires the function to have no jumps or breaks—a function can be continuous but have a sharp corner or cusp where the derivative doesn't exist.

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