# Your code goes here
import numpy as np

def f(x, r):
    return r * x * (1 - x)

def iterate_f(x, r, n_iterations):
    trajectory = np.zeros(n_iterations+1)
    trajectory[0] = x
    for i in range(n_iterations):
        trajectory[i+1] = f(x, r)
        x = trajectory[i+1]
    return trajectory