code for diagram

> f:=t->sqrt(1+sin(t)):
p7:=plot(f(x),x=-1.5..4,thickness=3):
lines:=plot({[[-.75,0],[-.75,f(-.75)]],[[2.5,0],
[2.5,f(2.5)]]},thickness=3,linestyle=3):
txt:=plots[textplot]({[-.67,-.2, `u(t)`], [2.5,-.2,
`v(t)`],[1.5,1.8,`y =
sqrt(1+sin(x))`]},font=[TIMES,BOLD,16]):
plots[display]({p7,lines,txt},scaling=constrained,
xtickmarks=[-1,2,3],ytickmarks=[],axesfont=[TIMES,BOLD,14]);