modeling-app/docs/kcl-std/functions/std-math-cos.md

---
title: "cos"
subtitle: "Function in std::math"
excerpt: "Compute the cosine of a number."
layout: manual
---

Compute the cosine of a number.

```kcl
cos(@num: number(Angle)): number
```


### Arguments

| Name | Type | Description | Required |
|----------|------|-------------|----------|
| `num` | [`number(Angle)`](/docs/kcl-std/types/std-types-number) | A number. | Yes |

### Returns

[`number`](/docs/kcl-std/types/std-types-number) - A number.


### Examples

```kcl
exampleSketch = startSketchOn(XZ)
  |> startProfile(at = [0, 0])
  |> angledLine(angle = 30deg, length = 3 / cos(30deg))
  |> yLine(endAbsolute = 0)
  |> close()

example = extrude(exampleSketch, length = 5)

```

![Rendered example of cos 0](data:image/png;base64,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
Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00			`---`
Add subtitle to docs and fix primitive type links (#6724) Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-05-07 10:33:23 +12:00			`title: "cos"`
More docs fixes (#6733) * Fix various docs errors around std module Signed-off-by: Nick Cameron <nrc@ncameron.org> * remove KCL from lang docs titles and move settings docs Signed-off-by: Nick Cameron <nrc@ncameron.org> * Include functions declared in Rust in module docs Signed-off-by: Nick Cameron <nrc@ncameron.org> --------- Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-05-08 08:26:56 +12:00			`subtitle: "Function in std::math"`
Remove trig functions from prelude and change their unit handling (BREAKING) (#6565) Remove trig functions from prelude and change their unit handling Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-04-30 12:40:11 +12:00			`excerpt: "Compute the cosine of a number."`
Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00			`layout: manual`
			`---`

Remove trig functions from prelude and change their unit handling (BREAKING) (#6565) Remove trig functions from prelude and change their unit handling Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-04-30 12:40:11 +12:00			`Compute the cosine of a number.`
Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00
Some improvements to the boxed signatures in the docs (#6593) * Show a more reasonable name in function docs Signed-off-by: Nick Cameron <nrc@ncameron.org> * Fix buggy docs for union types Signed-off-by: Nick Cameron <nrc@ncameron.org> * Make types in the docs signatures into links Signed-off-by: Nick Cameron <nrc@ncameron.org> --------- Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-05-01 04:03:22 +12:00			```kcl
Change trig functions to return number with Default units (#7425) * Change trig functions to return number with Default units * Update docs * Update output 2025-06-10 20:24:48 -04:00			`cos(@num: number(Angle)): number`
Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00			```

Add subtitle to docs and fix primitive type links (#6724) Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-05-07 10:33:23 +12:00

Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00			`### Arguments`

			`\| Name \| Type \| Description \| Required \|`
			`\|----------\|------\|-------------\|----------\|`
Docs content (#6792) * Add documentation to modules, and some constants and types Signed-off-by: Nick Cameron <nrc@ncameron.org> * Improve the language reference Signed-off-by: Nick Cameron <nrc@ncameron.org> --------- Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-05-11 19:32:33 +12:00			\| `num` \| [`number(Angle)`](/docs/kcl-std/types/std-types-number) \| A number. \| Yes \|
Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00
			`### Returns`

Change trig functions to return number with Default units (#7425) * Change trig functions to return number with Default units * Update docs * Update output 2025-06-10 20:24:48 -04:00			[`number`](/docs/kcl-std/types/std-types-number) - A number.
Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00

			`### Examples`

Some improvements to the boxed signatures in the docs (#6593) * Show a more reasonable name in function docs Signed-off-by: Nick Cameron <nrc@ncameron.org> * Fix buggy docs for union types Signed-off-by: Nick Cameron <nrc@ncameron.org> * Make types in the docs signatures into links Signed-off-by: Nick Cameron <nrc@ncameron.org> --------- Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-05-01 04:03:22 +12:00			```kcl
Declare std kwarg functions in KCL and migrate circle (#5955) * Support calling KCL std KW fns, and move circle to KCL std Signed-off-by: Nick Cameron <nrc@ncameron.org> * Doc comments on parameters Signed-off-by: Nick Cameron <nrc@ncameron.org> * Update grammar Signed-off-by: Nick Cameron <nrc@ncameron.org> * Change use of counterClockWise to ccw Signed-off-by: Nick Cameron <nrc@ncameron.org> --------- Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-03-24 21:55:24 +13:00			`exampleSketch = startSketchOn(XZ)`
Kwargs: startProfileAt (#6424) Previous: ``` startProfileAt([x, y], %) startProfileAt([x, y], sketch001) ``` New: ``` startProfile(%, at = [x, y]) startProfile(sketch001, at = [x, y]) ``` 2025-04-25 16:01:35 -05:00			`\|> startProfile(at = [0, 0])`
Units bug fix with modulo (#7446) * Add degrees annotations to examples Signed-off-by: Nick Cameron <nrc@ncameron.org> * Fix a units bug with the modulo operation Signed-off-by: Nick Cameron <nrc@ncameron.org> --------- Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-06-12 08:44:55 +12:00			`\|> angledLine(angle = 30deg, length = 3 / cos(30deg))`
KCL: Convert x/y lines to use keyword arguments (#5615) Previously, `xLine`, `xLineTo`, `yLine` and `yLineTo` used positional arguments. Now: - `xLineTo` and `yLineTo` have been removed - `xLine` and `yLine` both use keyword arguments: - `length`, optional (i.e. a relative distance along the X or Y axis) - `endAbsolute` optional (i.e. an absolute point along the X or Y axis) - `tag` optional - Exactly one of `length` or `endAbsolute` must be given. Not both, not neither. For example: ``` // Old way \|> xLine(6.04, %) \|> yLineTo(20, %, $base) // New way \|> xLine(length = 6.04) \|> yLine(endAbsolute = 20, tag = $base) ``` This also improves some of the general-purpose keyword arguments code in modeling app's TS codebase. 2025-03-07 22:07:16 -06:00			`\|> yLine(endAbsolute = 0)`
Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00			`\|> close()`

			`example = extrude(exampleSketch, length = 5)`
Format examples in docs (#7378) Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-06-06 10:01:45 +12:00
Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00			```

Add subtitle to docs and fix primitive type links (#6724) Signed-off-by: Nick Cameron <nrc@ncameron.org> 2025-05-07 10:33:23 +12:00			![Rendered example of cos 0](data:image/png;base64,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
Declare parts of std in KCL rather than Rust (#5147) Declare std in KCL 2025-02-20 19:33:21 +13:00