ATAN Function (LibreOffice Calc)
The ATAN function returns the arctangent (inverse tangent) of a number. The result is an angle expressed in radians and is widely used in trigonometry, geometry, physics, and engineering.
Compatibility
▾| Excel | ✔ |
| Gnumeric | ✔ |
| Google_sheets | ✔ |
| Libreoffice | ✔ |
| Numbers | ✔ |
| Onlyoffice | ✔ |
| Openoffice | ✔ |
| Wps | ✔ |
| Zoho | ✔ |
What the ATAN Function Does ▾
- Computes the inverse tangent of a value
- Returns an angle in radians
- Accepts any real number
- Useful for slope calculations, vector angles, and geometric modeling
Syntax ▾
ATAN(number)
Arguments
- number:
Any real numeric value.
Basic Examples ▾
Arctangent of a value
=ATAN(1)
→ 0.785398163 (π/4 radians)
Convert result to degrees
=DEGREES(ATAN(1))
→ 45
Using a cell reference
=ATAN(A1)
Advanced Examples ▾
Compute angle of a slope (rise/run)
=DEGREES(ATAN(Rise / Run))
Angle between two vectors (tangent form)
=ATAN((A1*B2 - A2*B1) / (A1*B1 + A2*B2))
Normalize input for stability
=ATAN(VALUE(A1))
Compute arctangent using logarithmic identity (complex domain)
=IMDIV(IMSUB(IMLN(1 + IMSEC(A1)); IMLN(1 - IMSEC(A1))); 2*IMAGINARY(0))
Use ATAN with ATAN2 for full quadrant awareness
=ATAN2(Y; X)
Edge Cases and Behavior Details ▾
ATAN returns a numeric value (radians)
Accepts:
- Any real number
- Expressions that evaluate to numbers
Behavior details
- Domain is (–∞, ∞)
- Output is in radians
- ATAN(0) returns 0
- ATAN does not determine the correct quadrant — use ATAN2 for that
Invalid input → Err:502 (non-numeric)
ATAN of an error → error propagates
Common Errors and Fixes ▾
Err:502 — Invalid argument
Cause:
- Input is text
- Input cannot be coerced to a number
Fix:
- Convert text to number with VALUE
- Validate numeric input
Unexpected angle
Cause:
- Forgetting ATAN returns radians
- Using ATAN instead of ATAN2 for quadrant-sensitive calculations
Fix:
- Wrap with DEGREES
- Use ATAN2(X; Y) when direction matters
Best Practices ▾
- Convert to degrees for human‑readable angles
- Use ATAN2 when both X and Y components are known
- Combine with ACOS and ASIN for complete inverse‑trig workflows
- Validate numeric input for stability
ATAN is your inverse‑tangent workhorse — essential for geometry, physics, engineering, and any model involving slopes or directional angles.
Related Patterns and Alternatives ▾
- Use TAN for forward tangent
- Use ATAN2 for full 2‑axis angle calculations
- Use DEGREES and RADIANS for angle conversion
- Use PI() for circle and rotation calculations
By mastering ATAN and its companion functions, you can build precise, reliable trigonometric and geometric models in LibreOffice Calc.