# Logic - Derivation Help Please?

1. Mar 24, 2010

### Brcummings

Do a derivation showing that (P conditional Q) v P is a theorem of system SD+

*Sorry guys, I can't figure out how to do the symbol in between (P Q), but it means If P then Q and it is otherwise known as the conditional

-I am really struggling with this problem and I would greatly appreciate any help

2. Mar 25, 2010

### Staff: Mentor

What is system SD+?

Make a truth table with separate columns for P, Q, $P \Rightarrow Q$, and $P \Rightarrow Q \vee P$

You need four rows.

To see how I got the "implies" arrow or the V, double-click the expressions that use these symbols, and another window with the LaTeX code opens.