set title "Error in solution of 2-pt BVP using O(h^4) FDA  (levels 4, 5, 6)"
set key 0.2,0.0008
set xlabel "x"
set ylabel "u_exact(x) - u(x)"
set terminal postscript portrait
set size 0.760,1.0
set output "err456.ps"
plot "err4" t "level 4", "err5" t "level 5", "err6" t "level 6" 
quit