Let z∼n(0,1). if we define x=eσz+μ , then we say that x has a log-normal distribution with parameters μ and σ, and we write x∼lognormal(μ,σ).
(a) if x∼lognormal(μ,σ), find the cdf of x in terms of the φ function.
(b) find pdf of x, ex and var(x).

Find the directions in which the function increases and decreases most rapidly at upper p 0p0. then find the derivatives of the function in these directions. f(x,y)equals=x squared plus xy plus y squaredx2+xy+y2, upper p 0p0left parenthesis 1 comma negative 4 right parenthesis