MATLAB

quadform:

function [x1,x2] = quadform(a,b,c)

d = sqrt(b^2 - 4*a*c);

x1 = (-b + d) / (2*a);

x2 = (-b - d) / (2*a);

Write a function quadform2 that implements the quadratic formula differently from quadform above (page 19). First compute

x1 = (bsign(b)sqrt(b^2 - 4ac))/ 2a

which is the root of largest magnitude, and then use the identity x1x2 = c/a to find x2.

Apply both quadform and quadform2 to find the roots of x2 (10^7 + 10^7)x + 1. Do you see why quadform2 is better?