j

hw2-j.text

       program hw2
       implicit none
       real x
       double precision y
       double precision z
       integer i
       double precision h
       double precision q

       
       h=1.0
	   x=0.5


	   do i=0,10

	   y=x+h
	   z=x-h

	   q=(f(y)-f(z))/(2.0*h)

	   write(*,*) h,q

	   h=h*0.1

	   end do



	   contains
	   function f(y)
	   double precision y, f
	   f=-0.1*y**4-0.15*y**3-0.5*y**2-0.25*y+1.2
	   return
	   end function f


	   





















       end program hw2