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<DIV>Dear Group Pstricks,<BR>my name is Sebastiano Spatola and I am a doctor in
Mathematica and physics for students of high school. I worked </DIV>
<DIV>I use from more of a Latex year and I have discovered from little days
the metapost of 2D and 3D. However to create a figure with labels,
headings I </DIV>
<DIV>I must insert any codes in a source .tex </DIV>
<DIV><FONT face=Arial size=2>
<DIV>\listfiles<BR>\documentclass[a4paper]{article}% Herbert Voss
2004-10-06<BR>\usepackage{pstricks}<BR>\usepackage{pstricks-add}<BR>\usepackage{multido}<BR>\def\func{%<BR>
const0 x sin dup mul 3 mul div neg /p exch def<BR> p abs sqrt
neg /r exch def<BR> const1 2.0 div neg /q exch
def<BR> p 0 lt {<BR> p dup mul p
mul q dup mul add 0 le {<BR> q r 3 exp
div arccos <BR> 3 div cos r dup add
neg mul<BR>
}{<BR> q r 3 exp div
arch<BR> 3 div cosh r dup add neg
mul<BR> } ifelse<BR>
}{<BR> q r 3 exp div
arsh<BR> 3 div sinh r dup add neg
mul <BR> }
ifelse<BR>}<BR>\begin{document}<BR>\textbf{Dynamical flow around a
cylinder}<BR>\[<BR>\left(r^2-\frac{c_1}{r}\right)\sin^2\theta=c_0<BR>\]</DIV>
<DIV> </DIV>
<DIV>which is the same as</DIV>
<DIV> </DIV>
<DIV>\[<BR>r^3-\frac{c_0}{\sin^2\theta}\cdot r-c_1=0<BR>\]</DIV>
<DIV> </DIV>
<DIV>which can be solved by the formula of Cardano:</DIV>
<DIV> </DIV>
<DIV>\[<BR>r^3+3pr+2q=0<BR>\]</DIV>
<DIV> </DIV>
<DIV>\bigskip<BR>\begin{pspicture*}(-5,-2.5)(5,2.5)<BR>
\pstVerb{<BR> /e 2.718281828459045 def<BR>
/arccos { dup dup mul neg 1.0 add sqrt exch atan } def<BR>
/sinh { dup e exch exp exch neg e exch exp sub 2 div } def<BR>
/cosh { dup e exch exp exch neg e exch exp add 2 div } def<BR>
/arsh { dup dup mul 1 add sqrt add ln } def<BR> /arch { dup
dup mul 1 sub sqrt add ln } def<BR> }<BR>
\psaxes(0,0)(-5,-2.5)(5,2.5)<BR> \pscircle[linecolor=red]{1}<BR>
\psset{plotpoints=100,linewidth=0.05pt,polarplot=true,linecolor=blue}<BR>
\multido{\rA=0.005+0.05}{5}{<BR>
\psplot{1}{179}{%<BR> /const0 \rA\space def
<BR> /const1 1.0 def % cylinder
radius<BR> \func<BR>
}<BR> \psplot{181}{359}{%<BR>
/const0 \rA\space def <BR> /const1 1.0 def %
cylinder radius<BR> \func<BR>
}%<BR> }<BR> \multido{\rA=0.03+0.25}{20}{<BR>
\psplot{1}{179}{%<BR> /const0 \rA\space def
<BR> /const1 1.0 def % cylinder
radius<BR> \func<BR>
}<BR> \psplot{181}{359}{%<BR>
/const0 \rA\space def <BR> /const1 1.0 def %
cylinder radius<BR> \func<BR>
}%<BR> }<BR>\end{pspicture*}</DIV>
<DIV> </DIV>
<DIV>\end{document}</DIV></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><BR>But doesn't exist a program that creates me the inverse Polish
notation, interval, etc? How long want to understand first and then to write the
codes of a figure?<BR>Not understand nothing when I must to draw a function in
2D and 3D. For example; if I must to draw the function x*\sqrt(x^2+y^2-1)
or the area of the trapezoid of the function x +sin x in the interval
[\pi/2 3/4 \pi] as I have to do? Want years to understand as create
only a simple figure; represent of behaviour a give a complex figure.
But doesn't exist a program that creates me directly the code that
transforms me a function in the inverse Polish notation and that to draw
it?</DIV>
<DIV>I hope you sent me a answer of my problem.</DIV>
<DIV>Best regards </DIV>
<DIV>Sebastiano Spatola</DIV></FONT></DIV></BODY></HTML>