set term png

set out "z1.png"

set xl "t"
set yl "y(t)"


set title "Metoda Eulera"
plot "zad1.txt" u 1:2 w p pt 3 t "dt=0.01" , "zad2.txt" u 1:2 w p pt 6 t "dt=0.1", "zad3.txt" u 1:2 w p pt 6 t "dt=1", exp(-x) w l lw 2 t "analityczne"