COS Function in SoftMaker PlanMaker 2026: Syntax, Examples & Troubleshooting

On a unit circle, COS(angle) is the horizontal coordinate. For a right triangle, it is the adjacent side divided by the hypotenuse. SoftMaker explicitly requires radians, not degrees: the formula =COS(60) means 60 radians. For 60°, convert first using =COS(RADIANS(60)) (or equivalently =COS(60*PI()/180)).

=COS(Number)

There are no documented optional arguments. SoftMaker’s PlanMaker 2026 English page specifically demonstrates COS(PI()) → −1 and COS(RADIANS(180)) → −1. The other values below are mathematical calculations performed outside PlanMaker.

Why a right angle might not display as 0: Independent IEEE floating-point evaluation of COS(PI()/2) produces a very small residual. PlanMaker’s exact internal result has not been tested here; avoid direct equality to zero. A defensible tolerance-based test is =ABS(COS(RADIANS(90)))<0.000000001.

Type Degrees, Radians, Cosine, Expected into A1:D1. Set A2:A7 to 0, 30, 60, 90, 180, 270. Enter =RADIANS(A2) in B2, =COS(B2) in C2, and copy both formulas down through row 7. The mathematical expected values in C2:C7 are:

Set D2:D7 to the mathematical target values 1, 0.866025403784439, 0.5, 0, -1, 0. A comparison such as =ABS(C2-D2)<0.000000001 (copied down) is more reliable than testing exact equality against rounded text.

Horizontal component of a sloping length. Enter 12 (metres) in A2 and 30 (degrees from horizontal) in B2. =A2*COS(RADIANS(B2)) gives the independently computed projection 10.392304845 metres. The matching vertical component =A2*SIN(RADIANS(B2)) is 6 metres; by the Pythagorean identity, the squared components sum to 144 (subject to ordinary floating precision).

Rotate a point without losing its sine component. For X=4 in A2, Y=3 in B2, and rotation of 90° in C2, calculate the new X coordinate using =A2*COS(RADIANS(C2))-B2*SIN(RADIANS(C2)); the expected X is −3. New Y is =A2*SIN(RADIANS(C2))+B2*COS(RADIANS(C2)), expected 4. These are standard 2D rotation formulas; the application execution remains unverified.

A periodic reading. With baseline 100 in A2, amplitude 20 in B2 and phase angle 60° in C2, =A2+B2*COS(RADIANS(C2)) has the mathematical expected value 110. A cosine model starts at its peak when phase is zero (unlike a sine model); choose the function according to how your real-world cycle is defined.

• Degrees versus radians: This is the primary problem. =COS(60) does not mean COS(60°). Use RADIANS on degree data first.
• Unexpected microscopic result at 90° or 270°: Display near-zero values with an appropriate number format or compare numerically with a tolerance; exact zero should not be assumed.
• Incorrect or omitted argument: The vendor page documents precisely one numeric input, not an optional default. It does not enumerate error codes for all malformed or text inputs; inspect the exact installed build rather than importing Excel’s error table.
• Wrong sign: COS is negative for angles between 90° and 270° on the usual unit circle. If a geometry worksheet expects only positive lengths, verify its angle reference and interpretation rather than applying ABS automatically.
• Cosine outside the mathematical [−1, 1] range: Check the value you think is COS versus a formula that multiplies it by a length or amplitude. COS itself is dimensionless.
• Formula displays as text: SoftMaker requires = for manual entry. Ensure the target cell is evaluated as a formula.

• RADIANS: convert degrees
• SIN: sine
• ACOS: inverse cosine
• TAN: tangent
• PI: π constant

• PlanMaker 2026/NX: SoftMaker’s English function page documents the exact one-argument formula and its purpose. SoftMaker’s 2026 help is the primary basis for the PlanMaker-specific claims in this guide.
• PlanMaker 2024: The separate 2024 English reference describes the same one-argument signature and core calculation. That establishes documented continuity, not a tested equivalence across builds.
• Microsoft Excel: Microsoft’s own function reference also documents the same trigonometric/conversion operation and a single numeric angle argument. This is a documentation-level similarity. It does not establish identical handling of strings, empty cells, overflow, floating-point last digits or Excel file round-tripping.
• Edition/platform: The inspected PlanMaker 2026 English help is for the 2026/NX release family. Particular paid/free editions, Windows/macOS/Linux builds, mobile applications and configurations were not run. Do not infer per-edition availability merely from catalogue presence.
• Locale: Examples show English-function names, a period decimal point, and direct cell references. Each of these functions takes one argument, so these examples do not establish which separator a particular locale uses for multi-argument functions. SoftMaker documents configurable decimal/thousands separators and the Formula → Function dialogue. Check translated function names and locally accepted syntax in your installation before asserting locale equivalence.

Native validation checklist

Record the installed PlanMaker product/version/build, OS, edition, language/locale, calculation mode and workbook format. Enter the specified test cells; record displayed values with at least nine decimal places where relevant; inspect the formula bar rather than relying only on rounded displays. Test unexpected text and empty references in that native build to establish actual error behaviour. Save and reopen the native file, then independently verify .xlsx export/import and opening in an actual Excel build if the guide will promise interchange. None of these tests has been performed for this guide.

1. SoftMaker PlanMaker 2026/NX English manual, COS function: exact argument order, mathematical purpose, and vendor-labelled examples. Inspected 2026-10-13.
2. SoftMaker PlanMaker 2024 English manual, COS function: confirms same core documented signature and purpose. Inspected 2026-10-13.
3. Microsoft Excel help, Excel COS function: independently documents Excel’s corresponding syntax and degree/radian convention. Inspected 2026-10-13; not PlanMaker runtime evidence.
4. SoftMaker 2026, Entering formulas: the equals sign and Formula → Function UI. Inspected 2026-10-13.
5. SoftMaker 2026, Editing and numeric separator settings: locale/system input display settings. Inspected 2026-10-13.
6. SoftMaker 2026, DEGREES and PI: related conversion and mathematical constant. Inspected 2026-10-13.