program diff_sine
C
C  this is a program to illustate the derivate
C  of the sine function by Euler discretization
C
C  written 1/27/2005 C.W. Johnson SDSU
C
      print*,' enter x,dx '
      read*,x,dx
      f=sin(x)
      dfdx = (sin(x+dx)-sin(x))/dx
      print*,'   sin(x)      dsin/dx     cos(x) '
      print*,f,dfdx,cos(x)
      end