program deriv
      implicit none

      integer, parameter:: kr=selected_real_kind(13)
      real(kind=kr), dimension(8) ::h
      real(kind=kr) :: x, exact, deriv_simm
      integer :: i
      data h/.1_kr, .01_kr, .005_kr, .001_kr, .0005_kr, .0001_kr, .00001_kr, .000001_kr/
       x = 1._kr
       exact = cos(x)
       print*,"           h,      deriv_simm,   deriv_simm - exact"
        do i=1,8
       deriv_simm = (sin(x+h(i))-sin(x-h(i))) / (2*h(i))
       print*,  h(i), deriv_simm, deriv_simm - exact
       write(2,*) h(i),  deriv_simm, deriv_simm - exact
       end do
        do i=1,12
       deriv_simm = (sin(x+h(8)/(i*10))-sin(x-h(8)/(i*10))) / (2*h(8)/(i*10))
       print*,  h(8)/(i*10), deriv_simm, deriv_simm - exact
       write(2,*) h(8)/(i*10),  deriv_simm, deriv_simm - exact
       end do
       stop
       end program deriv