I'm relatively new to python but I have used loops in previous programs I have made but they were relatively simple. 
I was wondering if there was a method that involved a loop or some other way to make this iteration more concise.

Basically is there a way for me to have a variable called 't' that holds values for t1,t2 and t3 in like a list which is then used in 'eq' and 'der' instead of copying and pasting the same piece of code?

I have already tried to look for an answer on here and other places but the solutions I have found so far don't seem to work with what I have got/I'm not python literate enough to understand them.

```
import numpy as np
U235_Decay_Constant = 9.72e-10
U238_Decay_Constant = 1.54e-10

t0 = 4.1e9

eq = ((np.exp(U238_Decay_Constant*t0)-1)-(0.0167* 
((np.exp(U235_Decay_Constant*t0)-1)))-0.0094)
der = (U238_Decay_Constant*(np.exp(U238_Decay_Constant*t0)))-(0.0167* 
(U235_Decay_Constant*(np.exp(U235_Decay_Constant*t0))))

t1 = t0 - (eq/der)

eq = ((np.exp(U238_Decay_Constant*t1)-1)-(0.0167* 
((np.exp(U235_Decay_Constant*t1)-1)))-0.0094)
der = (U238_Decay_Constant*(np.exp(U238_Decay_Constant*t1)))-(0.0167* 
(U235_Decay_Constant*(np.exp(U235_Decay_Constant*t1))))

t2 = t1 - (eq/der)

eq = ((np.exp(U238_Decay_Constant*t2)-1)-(0.0167* 
((np.exp(U235_Decay_Constant*t2)-1)))-0.0094)
der = (U238_Decay_Constant*(np.exp(U238_Decay_Constant*t2)))-(0.0167* 
(U235_Decay_Constant*(np.exp(U235_Decay_Constant*t2))))

t3 = t2 - (eq/der)
print(t3)

```