rotate method

Complex rotate(
  1. double angleRadians
)

Implementation

Complex rotate(double angleRadians) {
  double cosTheta = math.cos(angleRadians);
  double sinTheta = math.sin(angleRadians);
  double newReal = _re * cosTheta - _im * sinTheta;
  double newImag = _re * sinTheta + _im * cosTheta;
  return Complex(newReal, newImag);
}