Answer:
Explanation:
A Turing machine (TM) is considered undecidable if there is no algorithm that can decide, in a finite amount of time, whether a given input string is accepted by the machine or not.
One common way to prove that a TM is undecidable is by using Rice's Theorem. Rice's Theorem states that, for a large class of computational problems, if a problem is nontrivial (i.e., there exist both positive and negative instances of the problem), it is undecidable.
Another way to prove the undecidability of a TM is by reducing the halting problem to it. The halting problem is the problem of determining, given a TM and an input string, whether the TM halts on the input or not. It has been proven that the halting problem is undecidable, so if you can show that the problem you are considering is equivalent to the halting problem, then you have proven that the problem is also undecidable.
These are just two of many ways to prove that a TM is undecidable. The exact proof will depend on the specific TM and problem in question.