File:Parabola circle.svg

# Author: Ika
# Date: 12/11/2014

set term svg font 'Times, 18' size 500,300
set output 'parabola_circle.svg'

# In this program, the parabola equation is y = x^2.
# The circle equation is x^2 + (y-0.5)^2 = 1/4.
# We make it parametric as x = sin(t), y = 0.5 + cos(t).

set multiplot

# The ratio of the height and width of the plot chart is 1/2 = 0.5.
set size ratio 0.5
set xrange [-1:1]
set yrange [0:1]
# Unit along the axes is 0.5.
set xtics 0.5
set ytics 0.5
# Draw the axes.
set xzeroaxis lt -1 lc rgb "black" lw 1
set yzeroaxis lt -1 lc rgb "black" lw 1
set grid

unset label
set key off

# Draw the parabola y=x^2.
plot x*x lc rgb "black" lw 2;
# Draw the circle by using the parametric equations.
set parametric                              
set trange [0:2*pi]
plot 0.5*sin(t), 0.5+0.5*cos(t) lc rgb "red" lw 3;
	
unset multiplot

set term x11
set output