def multiplicative_process(n,rate,dt):
    """
    A constant growth rate process
    
    Parameters
    ----------
    n : int
        Number of time steps
    rate : float
        Constant growth rate
    dt : TYPE
        Delta time between time steps
    """
    wealth = [1]
    time = [0]
    for i in range(n):
        wealth.append(wealth[-1]*rate)
        time.append(time[-1]+dt)
    return time, wealth