bewerking=bewerking2.proc

!if $taal=nl
    nivo_title=Bepaal de symmetrie-as
    lijn=de lijn 
!else
    nivo_title=Determine the "Symmetry-axis"
    lijn=the line
!endif
R=$graad
    !for n=1 to $aantal_sommen
	lastig=!randitem 1,0
	!if $graad = 0
	    R=$n
	!endif    
	
	!if $R = 1 
	    a=!randitem 2,3,4,5,6,7,8,9,10
	    b=!randitem 0,1,2,3,4,5,6,7,8,9,10    
	    c=!randitem 0,1,2,3,4,5,6,7,8,9,10
	!endif
	!if $R = 2  
	    a=!randitem 2,3,4,5,6,7,8,9,10
	    b=!randitem 0,1,2,3,4,5,6,7,8,9,10    
	    c=!randitem 0,1,2,3,4,5,6,7,8,9,10
	    A=!randitem -1,1
	    B=!randitem -1,1
	    C=!randitem -1,1
	    a=$[$A*$a]
	    b=$[$B*$b]
	    c=$[$C*$c]
	!endif
	!if $R = 3
	    a1=!randitem 2,3,4,5,6,7,8,9,10
	    b1=!randitem 0,1,2,3,4,5,6,7,8,9,10    
	    c1=!randitem 0,1,2,3,4,5,6,7,8,9,10
	    a2=!randitem 2,3,4,5,6,7,8,9,10
	    b2=!randitem 1,2,3,4,5,6,7,8,9,10    
	    c2=!randitem 1,2,3,4,5,6,7,8,9,10
	    a=$a1/$a2
	    b=$c1/$c2
	    c=$c1/$c2
	!endif
	!if $R >3 
	    a1=!randitem 2,3,4,5,6,7,8,9,10
	    b1=!randitem 0,1,2,3,4,5,6,7,8,9,10    
	    c1=!randitem 0,1,2,3,4,5,6,7,8,9,10
	    a2=!randitem 2,3,4,5,6,7,8,9,10
	    b2=!randitem 1,2,3,4,5,6,7,8,9,10    
	    c2=!randitem 1,2,3,4,5,6,7,8,9,10
	    A=!randitem -1,1
	    B=!randitem -1,1
	    C=!randitem -1,1
	    a=$A*$a1/$a2
	    b=$A*$c1/$c2
	    c=$A*$c1/$c2
	!endif
	    functie=($a)*x^2 + ($b)*x + ($c)
	    S=-1*($b)/(2*$a)
	    sommen=!append line $functie to $sommen 
	    sommen=!append line $S to $sommen 
	    sommen=!append line printtex($functie) to $sommen 
	    sommen=!append line printtex($S) to $sommen
    !next n        
    SOMMEN=!exec pari $sommen
    r=1
    FF=!shuffle f,g,h,k,p,w
    !for n=1 to $aantal_sommen
	functie$n=!line $r of $SOMMEN
	GOED$n=!line $[$r+1] of $SOMMEN
	som$n=!line $[$r+2] of $SOMMEN
	goed$n=!line $[$r+3] of $SOMMEN
        !if $keuze=1    
            F=!item $n of $FF
            som$n=$F\left( x \right)\,\,\,=\,\,\, $(som$n)
        !else
            som$n=y\,\,\,=\,\,\, $(som$n)
        !endif
	Goed$n=$lijn x = $(GOED$n)
	goed$n= x = \frac{-1 \cdot b}{2 \cdot a} = $(goed$n)
	r=$[$r+4]
    !next n
    
    !if $PLAATJE=1
        !for n=1 to $aantal_sommen
            plaatje$n=\
	    transparent white\
	    xrange $[$(GOED$n) - 3],$[$(GOED$n) + 3]\
	    yrange -40,40\
	    vline 0,0,blue\
	    hline 0,0,blue\
	    linewidth 2\
	    dvline $(GOED$n),0,red\
	    curve green,$(functie$n)
        !next n
    !endif



