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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.

[4]
a.

Determine whether the compound proposition ¬((rp)¬q))¬(rp)q is a tautology, a contradiction or neither.

Give a reason.

[2]
b.

Markscheme

    (A1)(A1)(ft)(A1)(ft)(A1)     (C4)

 

Notes: Award (A1) for each correct column.

For the “(rp)¬q” follow through from the “rp” column.

For the “¬((rp)¬q))” column, follow through from the preceding column.

a.

tautology     (A1)(ft)

columns ¬((rp)¬q)) and ¬(rp)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 ¬((rp)¬q))¬(rp)q that is consistent with their table.

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Topic 3 - Logic, sets and probability » 3.1 » Basic concepts of symbolic logic: definition of a proposition; symbolic notation of propositions.

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