Newton-Raphson Method

def evaluate_poly(poly, x):
    valpoly = 0
    for i in range(0, len(poly)):
        valpoly = valpoly + (poly[i]*x**i) ## changed sumpoly to valpoly
    return valpoly ## return the value of poly at x



def compute_deriv(poly):
    deriv = ()
    for i in range(0, len(poly)):
        deriv = deriv + (poly[i]*i,)
    return deriv ## function returns a tuple representation of the derivative of "poly"



def compute_root(poly, x_0, epsilon):
    value = evaluate_poly(poly, x_0)
    count = 0

    while (value > epsilon) or (value < -epsilon):
        x_0 = x_0 - ((value)/(evaluate_poly(compute_deriv(poly), x_0)))
        value = evaluate_poly(poly, x_0)
        count += 1

    return (x_0, count)


polyMy = (-13.39, 0.0, 17.5, 3.0, 1.0)
print compute_root(polyMy, .01, .0001)
## Output should be (0.80679042259850975, 15239)