' - -  File: VIII_Mullti1.txt

' This unit combines several commands. Here, we plot the directed field, and then generate
'      a slope from the directed field at right angles, as explained in the Walkthru.
' Set h = 0.1 increment.

F{x,y} = 1
H{x,y} = 2*x*y
K{x,y} = - H{x,y}

a = -3  :  b = 3  :  n = 10
c = -3  :  d = 3  :  m = 10

x1 = 1  :  y1 = 2
x2 = 2  :  y2 = 3
x3 = -2  :  y3 = 1
x4 = -1.5  :  y4 = 0
x5 = 0  :  y5 = -2
x6 = 0.5  :  y6 = 1

PlotDirField[H,F, {a,b,n}{c,d,m}]        ' (x,y) --> <H,F> = <2xy, 1>

K{x,y} = -H{x,y}      '  and is the negative inverse of mapping  1 / 2xy = rt-angle.

PlotSlopeField[K, {a,b,n}{c,d,m} {x1,y1}{x2,y2}{x3,y3}{x4,y4}{x5,y5}]



