COS returns the cosine of an angle, with its input measured in radians. =COS(0) is expected to return 1; =COS(RADIANS(60)) should return approximately 0.5. The second formula demonstrates how to use degree-based worksheet data safely. Results in this guide are independent numerical expectations, not Calligra execution observations.

=COS(angle)

angle (required) is one floating-point numeric value, expression or numeric cell reference in radians. There is no optional second argument or default. COS returns a floating-point number. For real inputs, cosine lies between -1 and 1; the function does not return an angle and does not automatically interpret 60 as 60°. Negative inputs are allowed mathematically: cosine is even (cos(-x) = cos(x)).

The official KDE stable-KF6 handbook documents COS(Float) and examples COS(0) = 1, COS(PI()/2) = 0. The source of Calligra 26.08.2, released 2026-10-08, registers the function in its trig module; neither source is a native runtime test. Referenced on 2026-10-11. No precise introduction version is established here.

Locale and formula entry: Begin with =. The official handbook uses ; between arguments for functions that need multiple inputs; COS has only one. Examples use English numeric punctuation (0.5). Localized decimal marks or formula punctuation may differ; verify using the application’s Insert → Function dialog. RADIANS (degrees to radians) and PI() (a constant) are separate functions.

1. Put the headers in row 1, then enter the numeric degrees below in column B. Leave off literal degree symbols from numeric cells.
2. In C2, type =COS(RADIANS(B2)); copy it down to C6.
3. Display at least six decimals so the signs and values are easy to audit. Expected answers below are rounded only for display.

Interpretation: Cosine is negative in quadrant II (between 90° and 180°). The same result for negative and positive angles of equal magnitude is a mathematical identity: COS(RADIANS(-60)) is also expected to be about 0.5. =COS(PI()) is expected to be -1.

An object moves 100 metres at 30° above the horizontal. Put E2 = 100 (length) and F2 = 30 (degrees). Enter in G2:

=E2*COS(RADIANS(F2))

Expected horizontal component: 86.602540 m. To calculate the corresponding vertical component in H2, enter =E2*SIN(RADIANS(F2)), whose expected result is 50 m. This pair is useful for engineering diagrams, graphics, and resolving velocity or force. State your coordinate convention before interpreting signed components. If the length and angle refer to a compass bearing instead of a mathematical angle, convert to a consistent axis first.

Advanced consistency check

In the original table, enter J2 = 30 as a numeric angle in degrees. In K2 enter:

=COS(RADIANS(J2))^2+SIN(RADIANS(J2))^2

The expected result is 1, because sine squared plus cosine squared equals one. If a very small floating-point discrepancy appears, consider a tolerance rather than exact equality; that behavior was not tested natively.

• Degrees versus radians: COS(60) means 60 radians. To use sixty degrees, write COS(RADIANS(60)).
• Unexpected negative result: COS(120°) is negative. Check which quadrant your input represents before reversing the sign.
• A tiny nonzero at 90°: Floating-point approximations may show a residual close to 0 for COS(PI()/2); the handbook’s zero example is a mathematical ideal, not a guarantee of bit-exact zero. For comparisons, use ABS(value)<tolerance when suitable.
• Numbers stored as text: Remove literal degree symbols, extra spaces and incorrect decimal punctuation; check that references point to numeric cells.
• Formula error or blank-looking result: Confirm the leading =, parentheses, function spelling and cell format. KDE’s Simple Sums guide explains #VALUE! syntax issues and narrow-cell display warnings, but exact error codes for all COS inputs are not established here.
• Outdated display: Check recalculation settings and refresh with Tools → Recalculate Sheet if necessary; menu labels can vary by installed version.

COS is a standard radian-input function in Excel and LibreOffice Calc as well. All should agree in ordinary, well-formed numeric examples within floating-point precision; do not assume exactly identical last decimals, formula separators, text coercion, localized names or error rendering. In an imported .xlsx or .ods, spot-check the formulas and calculated values in the target application. Those import/export cases have not been tested for this guide.

The planned SIN, TAN, RADIANS and DEGREES articles are not yet live and therefore are deliberately not linked as published. The source-confirmed IF guide is relevant to numeric guards; the owner snapshot establishes its source path, not its public deploy status. Calligra function index is a proposed internal navigation route requiring live publication verification.

• Official Calligra COS entry and RADIANS, stable KF6, accessed 2026-10-11.
• Pinned KDE Calligra 26.08.2 trig source, source registry, not execution.
• KDE Gear 26.08.2 release announcement, dated 2026-10-08.
• KDE formula-entry and recalculation guide, accessed 2026-10-11.
• LibreOffice Calc mathematical functions, Excel RADIANS documentation, cross-program context, accessed 2026-10-11.

• Calligra Sheets — function documentation
• Simple Sums guide
• RADIANS
• Pinned KDE Calligra 26.08.2 trig source
• KDE Gear 26.08.2 release announcement
• LibreOffice Calc mathematical functions

Verification status: Official documentation checked; example outcomes were independently reasoned or arithmetically checked where applicable. Not executed in Calligra Sheets.

• No genuine Calligra Sheets screenshots are included; this guide does not use mock application images.