text: #ifndef DERIVATIVEMATRIX_H
  #define DERIVATIVEMATRIX_H
  
  
  void derivativeMatrix(double *DerivativeMatrix,unsigned N);
  
  void twoDDerivativeMatrixX(double *DerivativeMatrix, unsigned N);
  
  void twoDDerivativeMatrixY(double *DerivativeMatrix, unsigned N);
  
  #endif
  