Use the result of Exercise 5.3 to show that for the Bernoulli distribution, (a) 3 = 1

Use the result of Exercise 5.3 to show that for the Bernoulli distribution,
(a) α3 = 1 – 2θ / √(1 - θ), where α3 is the measure of skewness defined in Exercise 4.26 on page 129;
(b) α4 = 1 – 3θ(1 - θ) / √(1 - θ), where α4 is the measure of peakedness defined in Exercise 4.27 on page 129.