Help in proving a tautology I am having real trouble deriving this tautology:
$\forall(x) ((x=a) \lor (x\neq a))$
It is easy to solve this by assuming the negation, unpack the negation with DeMorgan's Law, and derive from there.
I am not allowed to use DeMorgan's however. Because of this I am at loss.
Any help will be greatly appreciated. Thank you!

It's not clear in your question what are we allowed to do, anyway here is a hint:
First note that $x \neq a$ is nothing but $\neg x = a$, hence we should prove that:
$$\vdash \forall x (x=a \vee \neg x=a)$$
Now recall  that 

$\alpha \rightarrow \beta \equiv \alpha \vee \neg \beta$ 

Now isn't there an implicational tautology you could easily prove instead of $x=a \vee \neg x=a$?
