As we mentioned for the binomial distribution (see Chapter 34, Exercise 34.3), we usually work with the log-likelihood function rather than the likelihood function for finding the MLE. Write out an expression for the Poisson log-likelihood, log {L(λ ; x)}, where as usual log indicates the natural log, ln. Differentiate log {L(λ ; x)} to find the maximum, and hence show that you obtain the same MLE for λ as you did in Exercise 38.7.