# Author: Ika, 2013-07-24
set term svg size 800,600 enhanced font 'Times,12'
set output 'Second_Order_Taylor.svg'

set multiplot

set xlabel "x"
set ylabel "y"
set zlabel "z"
set xrange [-1.0:2.0]
set yrange [-0.5:2.0]
set zrange [-6.0:10.0]
set box
unset colorbox
#set view 65,45
set style fill solid 0.30 border

set cntrparam levels auto 20
set contour base
set isosamples 60,60
set samples 60,60
set pm3d
set hidd
unset key
set ticslevel 0
i = {0.0,1.0}

# Draw the surface of f(x,y) = e^x log(1+y)
set palette defined (-1 "blue", 1 "pink")
splot exp(x)*log(1+y)

# Draw the surface of f(x,y) = y+xy-y^2/2
set palette defined (-1 "red", 1 "orange")
splot y+x*y-y*y/2

# Draw the lines
unset cntrparam
unset contour
set isosamples 20,20
set samples 20,20
unset pm3d
unset hidd

# Draw the lines of f(x,y) = e^x log(1+y)
splot exp(x)*log(1+y) lt 2 lc rgb "black" lw 0.1

# Draw the lines of f(x,y) = y+xy-y^2/2
splot y+x*y-y*y/2 lt 2 lc rgb "black" lw 0.1

unset multiplot
set term x11
set output