> For the complete documentation index, see [llms.txt](https://osl.mistium.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://osl.mistium.com/methods/numbers/trigonometry.md).

# Logarithms & Trigonometry

Logarithms and trigonometric functions. Trig comes in **degree** and **radian** variants.

## Logarithms

#### `.log()` → `number`

Base-10 logarithm.

#### `.ln()` → `number`

Natural (base-*e*) logarithm.

```javascript
log (100).log()  // 2
log (100).ln()   // 4.605170185988092
```

## Trigonometry (degrees)

| Method    | Description                     |
| --------- | ------------------------------- |
| `.sin()`  | Sine (input in degrees).        |
| `.cos()`  | Cosine (input in degrees).      |
| `.tan()`  | Tangent (input in degrees).     |
| `.asin()` | Arcsine (result in degrees).    |
| `.acos()` | Arccosine (result in degrees).  |
| `.atan()` | Arctangent (result in degrees). |

```javascript
log (30).sin()   // 0.5
log (180).cos()  // -1
```

## Trigonometry (radians)

| Method      | Description                 |
| ----------- | --------------------------- |
| `.radSin()` | Sine (input in radians).    |
| `.radCos()` | Cosine (input in radians).  |
| `.radTan()` | Tangent (input in radians). |

> Convert between the two with the built-in functions `degtorad(d)` and `radtodeg(r)`. The full set of mathematical functions and constants lives in the [`math`](/packages/mathtime/math.md) package.