Chain rule and product rule?

[Anon.ilbe]

Im stuck on theorem 5 where the book used chain rule then used product rule then again using the chain rule. How in the world does it work? I dont get product rule used and chain rule used after.

 

[SteamKing]

Im stuck on theorem 5 where the book used chain rule then used product rule then again using the chain rule. How in the world does it work? I dont get product rule used and chain rule used after.

Gee, it would really be nice if we got a look at that expression in part (a), as mentioned in the text.