f = lambda x: x * x * x - 3 * x * x + 2 * x

step = 0.001 # Smaller step values produce more accurate and precise results
start = -1
stop = 3

sign = f(start) > 0

x = start
while x <= stop:
    value = f(x)

    if value == 0:
        # We hit a root
        print "Root found at", x
    elif (value > 0) != sign:
        # We passed a root
        print "Root found near", x

    # Update our sign
    sign = value > 0

    x += step