// draws a polynomial

clear; //you have to clear variables before startng

x=-2:0.001:2;  

// x is input variable, a row vector x(0)=-2, x(1)=-2+0.001,...,x(n)=2

a0 = 1;
a1 = -1;
a2 = 2;

y= a0 + a1*x + a2*x^2; // calculates function component by component

plot(x,y);