# Дифференцирование 
## Ссылка на видеоразбор
https://youtu.be/Kh0shn9UW6Y
## Код из книги
    #let rec differentiate x tm = match tm with
    Var y -> if y = x then Const "1" else Const "0"
    | Const c -> Const "0"
    | Fn("-",[t]) -> Fn("-",[differentiate x t])
    | Fn("+",[t1;t2]) -> Fn("+",[differentiate x t1;
    differentiate x t2])
    | Fn("-",[t1;t2]) -> Fn("-",[differentiate x t1;
    differentiate x t2])
    |    Fn("*",[t1;t2]) ->
    Fn("+",[Fn("*",[differentiate x t1; t2]);
    Fn("*",[t1; differentiate x t2])])
    | Fn("inv",[t]) -> chain x t
    (Fn("-",[Fn("inv",[Fn("^",[t;Const "2"])])]))
    | Fn("^",[t;n]) -> chain x t
    (Fn("*",[n; Fn("^",[t; Fn("-",[n; Const "1"])])]))
    | Fn("exp",[t]) -> chain x t tm
    | Fn("ln",[t]) -> chain x t (Fn("inv",[t]))
    | Fn("sin",[t]) -> chain x t (Fn("cos",[t]))
    | Fn("cos",[t]) -> chain x t
    (Fn("-",[Fn("sin",[t])]))
    | Fn("/",[t1;t2]) -> differentiate x
    (Fn("*",[t1; Fn("inv",[t2])]))
    | Fn("tan",[t]) -> differentiate x
    (Fn("/",[Fn("sin",[t]); Fn("cos",[t])]))
    and chain x t u = Fn("*",[differentiate x t; u]);;