Reg ∩cfl
Regular Intersection with cfl is cfl acc to closure table properties .
Now the thing come when to use above matter it is used especially when language is not defined explicitly . So use closure table .
When language is directly given than result will be .
a^nb^n ∩∅=∅ ( which is regular so cfl also )
a^nb^n ∩⋲*=a^nb^n (which is cfl but not regular)