code: def derivative(self, x):
          
          if self.is_linear:
              return self
          else:
              return self.operator.derivative(self.vector * x) * self.vector
docs: Return the derivative at ``x``.
  
          Left vector multiplication and derivative are commutative:
  
          ``OperatorRightVectorMult(op, y).derivative(x) <==>
          OperatorRightVectorMult(op.derivative(x), y)``
  
          See Also
          --------
          OperatorRightVectorMult : the result