show that each wff is a tautology by using equivalences to show that each wff is equivalent to true.
a. A Av B.
b. AAB A.
c. (AV B) AA→B.
d. A→ (BA).
e. (AB) ABA.
f. (AB) ^ A → B.
g. A (B (A^ B)).
h. (A→B) ((A→→ B) → → A).