Relationship between NP-hard and undecidable problems

Question

Am a bit confused about the relationship between undecidable problems and NP hard problems. Whether NP hard problems are a subset of undecidable problems, or are they just the s

Answer 1

Undecidable problem e.g. Turing Halting Problem is NP-Hard only.

                   <---------NP Hard------>
|------------|-------------||-------------|------------|--------> Computational Difficulty

|<----P--->|

|<----------NP---------->|

|<-----------Exponential----------->|

|<---------------R (Finite Time)---------------->|

In this diagram, that small pipe shows overlapping of NP and NP-Hard and which shows NP-Completeness, i.e. set of those problems which are NP as well as NP-Hard.

Undecidable problems are NP Hard problems which do not have solution and which are not in NP.