นี่คือรหัสของฉัน: set term pdfcairo enhanced dashed size 5,3; set output "plot.pdf"; f(x,y)=sin(1.3*x)*cos(.9*y)+cos(.8*x)*sin(1.9*y)+cos(y*.2*x) set size square set xrange [-5:5] set yrange [-5:5] set contour base set cntrparam level incremental...