Date | May 2015 | Marks available | 4 | Reference code | 15M.1.sl.TZ2.5 |
Level | SL only | Paper | 1 | Time zone | TZ2 |
Command term | Complete | Question number | 5 | Adapted from | N/A |
Question
Consider the propositions r, p and q.
Complete the following truth table.
Determine whether the compound proposition ¬((r∧p)∨¬q))⇔¬(r∧p)∧q is a tautology, a contradiction or neither.
Give a reason.
Markscheme
(A1)(A1)(ft)(A1)(ft)(A1) (C4)
Notes: Award (A1) for each correct column.
For the “(r∧p)∨¬q” follow through from the “r∧p” column.
For the “¬((r∧p)∨¬q))” column, follow through from the preceding column.
tautology (A1)(ft)
columns ¬((r∧p)∨¬q)) and ¬(r∧p)∧q are identical (R1)(C2)
Notes: Do not award (R0)(A1)(ft). Follow through from their table in part (a).
Award the (R1) for an additional column representing ¬((r∧p)∨¬q))⇔¬(r∧p)∧q that is consistent with their table.