Doble for loop in Python : #my inner for loop is not using new values from outer loop, any help please

import numpy as np

a = 0.0000001

b = 15.

d = 0.1

TOL = 1.0e-6

a1 = []

dd = 0.1

da1 = []

for i in range(0,10):

    def f(v):
        return np.cosh(d * v) - (1./v) * np.sinh(d * v) - 1.
    FA = f(a)
    FB = f(b)
    for I in range(0,1000):
        p = a + (b - a) / 2.0
        FP = f(p)
        if FA == 0 or (b - a)/2.0 < TOL:
            break        
        I = I + 1
        if FA * FP > 0:
            a = p
            FA = FP
        if FA * FP < 0:
            b = p
    a1.append(p) 
    da1.append(d)
    d = d + dd
print a1
print da1