Hi Melody....thanks for your prompt reply.
![](/img/upload/b42f24e5b43cb462de92a986/ex-9e-no-10answer.jpg)
This is the answer (no 10) offered in the book which also differs from your solution......heck (2nd time I met this circumstance)!
re 'do more to show it is a Max value' : I extracted 2 nd derivative which is a negative...thus pointing to a maximum value.
Thanks for your feedback & knowledge!