C SIN(X) の二階微分の4次の近似式を用いた近似計算
      PROGRAM DF2SINR
      DOUBLE PRECISION DF2R,X,H
      INTRINSIC DSIN
      H=1.0D-1
      WRITE(*,*) 'Calculation of D2(SIN(X)) at X'
      WRITE(*,*)'Give X : '
      READ(*,*)X
          WRITE(*,*)'       H      &        4th Center  '
      DO 100 I=1,10
          WRITE(*,200)H,' & ',DF2R(DSIN,X,H),' \\\\'
          H=H/10
  100 CONTINUE
      WRITE(*,300)'True value -sin x : ',-DSIN(X)
  200 FORMAT(1H ,F13.10,A3,F22.16,A3)
  300 FORMAT(1H ,A20,F22.16)
      END
C
      DOUBLE PRECISION FUNCTION DF2R(F,X,H)
      DOUBLE PRECISION X,H,F
      EXTERNAL F
      DF2R=(-F(X+H*2)-F(X-H*2)+F(X+H)*16+F(X-H)*16-F(X)*30)/H/H/12
      RETURN
      END