# How to rotate a 2D point

In 2-D, the 2 × 2 matrix is very simple. If you want to rotate a column
vector `v` by `t` degrees using matrix `M`, use

`M = {{cos t, -sin t}, {sin t, cos t}}`

in `M * v`

.

If you have a row vector, use the transpose of `M` (turn rows into
columns and vice versa). If you want to combine rotations, in 2-D you can just
add their angles, but in higher dimensions you must multiply their matrices.

Original resource: | The Delphi Pool |
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Author: | Joseph O'Rourke |

Added: | 2013-04-09 |

Last updated: | 2013-04-09 |