Source code in the scilab programming language

a = 3;
b = 2;

theta = linspace(0,10*%pi,1000);
r = a + b .* theta;

//1. Plot using polar coordinates
scf(1);
polarplot(theta,r);

//2. Plot using rectangular coordinates
//2.1 Convert coordinates using Euler's formula
z = r .* exp(%i .* theta);
x = real(z);
y = imag(z);

scf(2);
plot2d(x,y);