Exponential-family derivative identities
= Exponential-family derivative identities
Differentiating the normalization identity gives
$$
A'(\theta)=\mathbb E_\theta T,
\qquad
A''(\theta)=\operatorname{var}_\theta T.
$$
= Exponential-family derivative identities
Differentiating the normalization identity gives
$$
A'(\theta)=\mathbb E_\theta T,
\qquad
A''(\theta)=\operatorname{var}_\theta T.
$$