This matrix rotates counterclockwise around the origin : matrix « Number « Ruby






  1. Ruby
  2. Number
  3. matrix

This matrix rotates counterclockwise around the origin


require "matrix"
unit = 2

theta = Math::PI/2     # 90 degrees
rotate = Matrix[[Math.cos(theta), -Math.sin(theta)],
                [Math.sin(theta),  Math.cos(theta)]]

rotate*unit            # [-1.0, 1.0]: 90 degree rotation








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