Exercise 2.4.5: Suppose a Cauchy sequence {𝑥𝑛} ∞ 𝑛=1 is such that for every 𝑀 ∈ ℕ, there exists a 𝑘 ≥ 𝑀 and an 𝑛 ≥ 𝑀 such that 𝑥𝑘 < 0 and 𝑥𝑛 > 0. Using simply the definition of a Cauchy sequence and of a convergent sequence, show that the sequence converges to 0.