Mathematical Italic Small F 𝑓

Visual Description: The symbol is a small, elegant italic f. It curves with a slight rightward tilt. It looks like a standard math italic letter, not a typed keyboard f. In formulas it marks a function. The shape helps distinguish functions from simple variables.

Meaning & Usage: The letter f is commonly used to name a function. It takes an input and returns an output, written as f(x) = y. In calculators or graphing tools, f labels the function you evaluate or graph. In code and math notes, f signals a rule rather than a fixed value.

Historical Background: In traditional typesetting, italics signify variables and function names. Math books standardized the use of italic letters for symbols like f to avoid confusion with constants. The practice spread to software and online tools, keeping the same visual cue. Keep the idea simple and readable.

Practical Use: In formulas, f often precedes x as f(x) to show a rule. Graphing calculators offer a dedicated function input and quick UI controls to compare f(x) values. In dashboards, you can press buttons to apply f to a data set or to test a condition like f(a) > f(b).

See our category page for related symbols.

Look‑alikes: f (U+66).

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