Exercise 4. In the lectures we have been working the the CRRA utility function, u: R+ ->R,which we defined, for any n ≥ 0, as u(x)=\left\{\begin{array}{ll} \frac{x^{1-\eta}-1}{1-\eta} & \text { if } \eta \in[0,1) \cup(1, \infty) \\ \ln x & \text { if } \eta=1 \end{array}\right. Prove that \lim _{\eta \rightarrow 1} \frac{x^{1-\eta}-1}{1-\eta}=\ln x

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