25 setxunit
-1.5 1.5 setxrange
-1.5 1.5 setyrange
80 setxunit
tracerepere
setTimes

/I {1 0} def
/J {0 1} def
/cerc {O 1} def

O point
cerc cercle
I point
J point
/x 28 def
/-x 90 x sub def

(O) O dltext
(I) I urtext
(J) J ultext

#tex# $x$
/X {x cerc cpoint} def
X dashpoint
X urtexlabel

#latex# $$\frac{\pi}{2}-x$$
/-X {-x cerc cpoint} def
-X dashpoint
-X urtexlabel

magenta O X (->) line
vert O -X (->) line

#tex# $\cos (x)$
magenta x cos 0 dctexlabel

#latex# $$\cos (\frac{\pi}{2}-x)$$
vert -x cos 0 dctexlabel

#tex# $\sin (x)$
magenta 0 x sin cltexlabel
#latex# $$\sin (\frac{\pi}{2}-x)$$
/fillstyle {blanc fill} def
0 setvadjust
0 setlinewidth
boxit
vert 0 -x sin cltexlabel