10. Let f(x) denote the probability density function of a normal random variable with mean and...

10. Let f(x) denote the probability density function of a normal random variable with mean μ and variance σ². Show that μ - σ and μ + σ are points of inflection of this function. That is, show that f''(x) = 0 when x = μ - σ

or x = μ + σ.