I Prove Logical Equivalence of P->(Q or R)

[The Subject]

From the text it says (P -> Q) or (P -> R) is equivalent to P -> (Q or R)

I tried to see if this is true so I tried
(P \to Q) \lor (P \to R) \\<br /> (P \lor \neg Q) \lor (P \lor \neg R) \\<br /> P \lor \neg Q \lor \neg R \\<br /> P \lor \neg(Q \land R) \\<br /> P \to (Q \land R)
and
P \to (Q \lor R) \\<br /> P \lor \neg(Q \lor R ) \\<br /> P \lor (\neg Q \land \neg R) \\<br /> (P \lor \neg Q) \land (P \lor \neg R) \\<br /> (P \to Q) \land (P \to R)

From what I've done its seems like they're not equivalent ?

 

[andrewkirk]

I tried
(P \to Q) \lor (P \to R) \\<br /> (P \lor \neg Q) \lor (P \lor \neg R)

The second line does not follow from the first.

I think what you meant to write for the second line was
$$(\neg P\vee Q)\vee (\neg P\vee R)$$
which is not the same thing.

 

[The Subject]

The second line does not follow from the first.

I think what you meant to write for the second line was
$$(\neg P\vee Q)\vee (\neg P\vee R)$$
which is not the same thing.

AHHHH thank you!