reset set border set xtics 1 set ytics 1 set xzeroaxis lt 9 lw 5 set yzeroaxis lt 9 lw 5 set style line 1 lt 1 lw 4 set style line 2 lt 3 lw 5 set style line 3 lt 10 lw 6 set style line 4 lt 12 lw 3 set style line 5 lt 9 lw 1 set grid ls 5 show grid set xrange [-9:9] set yrange [-10:10] set samples 1000 set key on h(x)=(x+2)/(x**2-9) j(x)=(x**2-9)/(x+2) k(x)=(x**2-9)/(x**4-8*x**2+16) # i(x)=4*x**2+40*x+84 # plot f(x) ls 1 # plot f(x) ls 1,g(x) ls 2, h(x) ls 3, i(x) ls 4 plot h(x) ls 1,j(x) ls 2, k(x) ls 3