## Basic Trigonometry Facts

### Algebra: Trigonometry Help

#### Home | Trig menu | Algebra menu

360 degrees = 2p radians

so, 180 degrees = p radians

The original angle can be found by using the inverse trig function. For example:

Sometimes in the literature, arcsin is written
as sin^{-1} and so on to indicate that it is an inverse function.

In the following examples, the side lengths are found using the Pythagorean theorem.

sin 45^{o} = cos 45^{o} = 1/1.4142 =
0.7071

tan 45^{o} = cot 45^{o} = 1/1 = 1

sin 30^{o} = cos 60^{o} = 1/2 =
0.5

cos 30^{o} = sin 60^{o} = 1.7321/2 =
0.8661

tan 30^{o} = cot 60^{o} = 1/1.7321 =
0.5774

cot 30^{o} = tan 60^{o} = 1.7321/1 =
1.7321

Then, there are the special cases of 0 and 90^{o}.

Angle | sin | cos | tan |
---|---|---|---|

0 | 0 | 1 | 0 |

90 | 1 | 0 | Infinity |

The sin and cos for the full circle (0 to 360^{o}) are
spelled out in the quadrant trigonometry facts
help page.

## Algebra: Trigonometry Help

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