bewerking=bewerking1.proc
mp=!randitem +,-
pm=!randitem +,-
gonio=!randitem sin,cos
!if $taal=nl
    nivo_title=Bepaal de <em>x</em>-waarden van de eerste twee snijpunten met de evenwichtslijn
    evenwichtslijn=evenwichtslijn
    xas=x-as
    yas=y-as
!else
    nivo_title=Determine the <em>x</em>-values of the first two intersection points with the "balance line"
    evenwichtslijn="balance line"
    xas=x-axis
    yas=y-axis
!endif
!if $graad=1
    c=!randitem 2*AA/9,AA/4,2*AA/7,AA/3,2*AA/5,4*AA/9,AA/2,4*AA/7,2*AA/3,4*AA/5,AA	
    p=!exec pari 2*AA/($c)
    c=!replace AA by pi in $c
    p=!replace AA by pi in $p
    a=!randitem -4,-3,-2,-1,1,2,3,4
    b=!randint 1,5
    !if $gonio=sin
	X1$n=0
	X2$n=!exec pari $p/2
	f$n=$a $mp $b*$gonio($c*x)
    !else
	X1$n=!exec pari $p/4
	X2$n=!exec pari $(X1$n)+$p/2
	f$n=$a $mp $b*$gonio($c*x)
    !endif
    letter=!item $n of $letters
    functie$n=!texmath $letter(x)=$(f$n)
    Y$n=$a
!endif

!if $graad=2
    c=!randitem AA,AA/2,AA/4,AA/6,AA/8,AA/10,AA/12,AA/14,AA/16,AA/18
    p=!exec pari 2*AA/($c)
    c=!replace AA by pi in $c
    p=!replace AA by pi in $p
    a=!randitem -4,-3,-2,-1,1,2,3,4
    b=!randint 1,5
    x=!randint 0,$p
    x=!exec pari $x/2
    X1$n=$x
    X2$n=!exec pari $x + $p/2
    !if $gonio=sin
	d=!exec pari (2*$(X1$n)/$p)
	d=$d*pi
	!if $d=0*pi
	    f$n=$a $pm $b*$gonio($c*x)
	!else
	    f$n=$a $pm $b*$gonio($c*x - $d)
	!endif
    !endif
    !if $gonio=cos
	e=!exec pari ((2*$(X1$n)/$p)-1/2)
	e=$e*pi
	!if $e=0*pi
	    f$n=$a $pm $b*$gonio($c*x)
	!else
	    f$n=$a $pm $b*$gonio($c*x - $e)
	!endif
    !endif
    letter=!item $n of $letters
    functie$n=!texmath $letter(x)=$(f$n)
    Y$n=$a
!endif

!for q=-1 to $[$(X2$n)+4] step 1
    V=vline $q,0,blue
    T=text black,$q,-0.3,normal,$q
    VLINE=!append line $V to $VLINE
    HTEXT=!append line $T to $HTEXT
!next q
Y1=$[$a -2*$b -1]
Y2=$[$a +2*$b +1]

!for q=$Y1 to $Y2
    H=hline 0,$q,blue
    T=text black,-0.3,$q,normal,$q
    HLINE=!append line $H to $HLINE
    VTEXT=!append line $T to $VTEXT
!next q

insdraw_animate=yes
ins_anim_loop=0
ins_anim_frames=2
ins_anim_delay=0.5
!if $printbaar=0
    clear=transparent white
    k1=blue
    k2=orange
    k3=red
    k4=green
    lijndikte=linewidth s*12
!else
    clear=transparent magenta 
    k1=black
    k2=black
    k3=black
    k4=black
    lijndikte=linewidth 10
!endif    
plaatje=$clear\
    xrange -1,$[$(X2$n)+4]\
    yrange $Y1,$Y2\
    linewidth 2\
    vline 0,0,$k1\
    hline 0,0,$k1\
    dhline 0,$a,$k2\
    text $k3,0,$a-0.1,huge,$evenwichtslijn\
    text $k3,$(X2$n),0.5,huge,$xas\
    textup $k3,-0.8,$[$Y2/3],huge,$yas\
    curve $k3,$(f$n)\
    $lijndikte \
    point $(X1$n),$a,$k1\
    point $(X2$n),$a,$k1

helpplaatje$n=$plaatje

plaatje$n=$plaatje\
    linewidth 1\
    $HLINE\
    $VLINE\
    $HTEXT\
    $VTEXT




