@acer Thanks for the explanation. This is a useful function to learn.

@acer Thanks for the explanation. This is a useful function to learn.

Thanks for the response and it works also. I am trying to understand this code. what does the third argument ([{'specfunc'('anything',min)},{}]) in frontend() for?

Thanks for the response and it works also. I am trying to understand this code. what does the third argument ([{'specfunc'('anything',min)},{}]) in frontend() for?

i guess the f() is indifferetiable (although continuous), so its derivitive will be discontinuous some where, while the derivitive got from above is continous

i guess the f() is indifferetiable (although continuous), so its derivitive will be discontinuous some where, while the derivitive got from above is continous

piecewise()  does more than I expect! and it works on my real problem, where I have more complicate condition

piecewise()  does more than I expect! and it works on my real problem, where I have more complicate condition