code for diagrams

> h:=x-> ((7*x+5)*exp(-x)+x*exp(x))/(exp(x)+exp(-x)):

> lpos:=plot(x,x=0..4,linestyle=3,color=red):

> lneg:=plot(7*x+5,x=-2..1,linestyle=3,color=brown):

> hplot:=plot(h(x),x=-2..4,color=blue):
pt1:=plots[display]({lpos,lneg,hplot},xtickmarks=[],ytickmarks=[],thickness=3): pt1;

> k:= piecewise(x<=0, x*sin(3*x),x^2/(x^2+1)):
kplot:=plot(k,x=-10..10):
pt2:=plots[display](kplot,xtickmarks=[],ytickmarks=[],thickness=3):pt2;