TAN Function
Returns the tangent of an angle given in radians.
Syntax
Parameters
| Parameter | Description | Required |
|---|---|---|
| number | The angle, in radians, for which you want the tangent. | Required |
Basic Example
Tangent of 45 degrees
=TAN(RADIANS(45))RADIANS(45) is π/4; the tangent of π/4 is 1.
Advanced Examples
Example 1: Tangent of 0
Baseline check.Tangent of zero radians.
=TAN(0)Example 2: Tangent of π/4
Quarter-eighth turn.Use PI()/4.
=TAN(PI()/4)How TAN Works
TAN computes the tangent of an angle measured in radians, equivalently SIN(number)/COS(number). The function is periodic with period π and is undefined (returns a very large magnitude) at π/2 + kπ, where cosine is zero.
Important Notes & Limitations
The angle must be in radians; degrees must be converted with RADIANS or PI()/180.
Near π/2 + kπ the result grows extremely large (approaching the undefined tangent).
Results are approximate due to floating-point math.
Common Errors & Fixes
Huge/odd resultAngle is close to π/2 (90°), where tangent is undefined.Fix: Check the angle; the value is mathematically approaching infinity.
#VALUE!Non-numeric argument.Fix: Supply a numeric angle.
Download Practice File
TAN
tanPractice TAN with Real Data
Download a sample CSV file with pre-populated data and practice exercises for the TAN function. Works in both Excel and Google Sheets.
File format: CSV (comma-separated values) - opens in Excel, Google Sheets, and all spreadsheet apps