>>> from quadratic import is_a_root

(x+1/2)(x-2) = 2x²-3x-2

>>> a, b, c = 2, -3, -2
>>> is_a_root(a, b, c, -0.5, 0.00001)
True

>>> is_a_root(a, b, c, -4, 0)
False

(x+1)(x-2/3) = 3x²+1x-2

>>> a, b, c = 3, 1, -2
>>> is_a_root(a, b, c, -1, 0)
True

>>> is_a_root(a, b, c, 0.66, 0.00001)
False

>>> is_a_root(a, b, c, 0.6666, 0.01)
True

>>> is_a_root(a, b, c, 1, 0)
False

(x-1/3)(x-4/3) = 3x²+1x-2

>>> a, b, c = 1, -5/3, 4/9
>>> is_a_root(a, b, c, 0.33, 0.00001)
False

>>> is_a_root(a, b, c, 0.33, 0.1)
True

>>> is_a_root(a, b, c, 1.33, 0.00001)
False

>>> is_a_root(a, b, c, 1.3333, 0.001)
True

(x+1)(x-3) = x²-2x-3

>>> a, b, c = 1, -2, -3
>>> is_a_root(a, b, c, -1, 0)
True

>>> is_a_root(a, b, c, 5, 0)
False