### Question:
Gaussian extends TransferFunction implements Serializable { @Override public double getDerivative(double net) { double derivative = output * ( -net / (sigma*sigma) ); return derivative; } Gaussian();  Gaussian(NeurophProperties properties); @Override double getOutput(double totalInput); @Override double getDerivative(double net); double getSigma(); void setSigma(double sigma);  }### Answer:
@Test public void testGetDerivative() { instance.getOutput(input); double result = instance.getDerivative(input); assertEquals(expected_derivative, result, FloatingAccuracy.ACCURACY); }