why is the given property of language non-trivial ?

Question

L={<M>|L(M) is regular } ,isn't it a trivial property because every TM accepts regular language.

Answer 1

Every Turing Machine accepts regular language? Whether yes or no does not matter (I guess you meant for every regular language we have a TM) because the property asked in question is the language of a Turing machine regular- this is true for some and false for some and hence is non-trivial.

Is the language of Turing machine r.e.? This is true for all TM, and hence is trivial.

Answer 2

FIRST OF ALL ITS UNDECIDABLE ....here the explanation

its similar to asking . does every program accepts the given input and rejects all thats not in input ...

and how u said that every TM accepts regular language ....u cant prove for all turing machine ...it will loop forever .