>    restart;

>    e:= x-> exp(-2*x);

e := proc (x) options operator, arrow; exp(-2*x) end proc

>    fsin := x-> Int(2*y/(Pi*(4+y^2))*sin(y*x), y=0..infinity);

fsin := proc (x) options operator, arrow; Int(2*y/Pi/(4+y^2)*sin(y*x),y = 0 .. infinity) end proc

>    fcos := x -> Int(4/(Pi*(4+y*y))*cos(y*x), y=0..infinity);

fcos := proc (x) options operator, arrow; Int(4/Pi/(4+y*y)*cos(y*x),y = 0 .. infinity) end proc

>    plot([e(x), fsin(x), fcos(x)], x=0..3, color = [black,black, blue]);

[Maple Plot]

>    plot(e(x), x=-3..3, color=black);

[Maple Plot]

>    plot(fcos(x), x=-3..3, color=black);

[Maple Plot]

>    plot(fsin(x), x=-3..3, color=black);

[Maple Plot]

>