Exercise 2.5 works, I think, but with some parameters it complains that there's a 'math domain error'
import math
def roots (a,b,c):
x = (math.sqrt(b**2 - 4*a*c)-b)/2
y = (-b - math.sqrt(b**2 - 4*a*c)-b)/2
print "x=",x
print "y=", y

Question

Exercise 2.5 works, I think, but with some parameters it complains that there's a 'math domain error'
import math
def roots (a,b,c):
    x = (math.sqrt(b**2 - 4*a*c)-b)/2
    y = (-b - math.sqrt(b**2 - 4*a*c)-b)/2
        print "x=",x
    print "y=", y

anonymous · Answer

You have to test the value of the discriminant before taking the square root.  Alternatively, if you can to do the optional part and have it produce complex root.  Takes a little bit of extra effort.  The sqrt function is still limited to non-negative values.  So take the sqrt of the absolute value and multiply by "1J"