Source
%% auteur : Peric
113.8 setxunit
596 setyunit
/xmarkstyle {[1.3 dup] dctext} def
/ymarkstyle {[1.3 dup] ultext} def
-2.3 1.4 setxrange
-0.25 0.45 setyrange
0.5 0.1 settkstep
0.5 0.1 setmkstep
ticks
marks
traceaxes
axesarrow
unites
/a{1.5}def
/f {setxvar
#rpn#   e^x-x/2-1
} def
/f' {setxvar
#rpn# 0
} def
/m{2 ln neg} def
/M{m f} def
/alpha{-1.593624260} def

m M dashpoint

gsave
  % bleu
m (f) tangente
   2 setlinewidth
   continu
   -2 0.5 {f} (*-*) Courbe
grestore
[-2	-1.8	-1.6	-1.4	-1.2	-1	-0.8	-0.6	-0.4	-0.2	0	0.5
] [0.135	0.065	0.002	-0.053	-0.099	-0.132	-0.151	-0.151	-0.130	-0.081	0.000	0.399] fuz {plus3} papply

gsave
#latex# $- \ln 2\approx -0,693$
m 0 [a dup] {-45} ultexlabel
%m 0 [a dup] uctexlabel
#latex# $\displaystyle\frac{\ln 2-1}2\approx -0,153$
0.1 M [a dup] crtexlabel
(S) m M [2 dup] dltext
#latex# $f(x)=\mathrm{e}^x-\displaystyle\frac{x}{2}-1$
-2 0.3 [a dup] crtexlabel
#latex# $\alpha$
alpha 0 [2 dup] dltexlabel
m 0 point
0 M point
grestore