Show that the following probability density functions are members of the exponential class of densities: (a) Binomial family, for a fixed value of n. (b) Poisson family. (c) Negative binomial family...

Show that the following probability density functions are members of the exponential class of densities:

(a) Binomial family, for a fixed value of n.

(b) Poisson family.

(c) Negative binomial family for a fixed value of r.

(d) Multinomial family, for a fixed value of n.

(e) Beta family.