KwickClips Computer Systems · 42 sec · free
How many rows make p → q false?
Short answer. Only one: p true, q false.
What is p → q when p is false?
True.
p → q
| p q | p → q | Promise |
|---|---|---|
| T T | T | kept |
| T F | F | broken |
| F T | T | not broken |
| F F | T | not broken |
Remember
| p → q false only for T, F |
Score ninety, get a cycle. When is this promise false? Take each row in turn. Both true: kept. Ninety, no cycle: broken. The last two rows never break it, so true. One rule. False only when p is true and q is false.
This clip is from the full lesson: Propositional Logic: Propositions, Connectives and Valid Formulae — 8 minutes, with the tables, the quick answers and the whole lesson in text.
Useful for: ISC Class 11 Computer Science (868), ISC Class 12 Computer Science (868), ISC Class 12 Computer Science (868)
More KwickClips from this lesson
Is a question a proposition?40 sec
Is p ∧ ~p a tautology?37 sec
Is every valid formula satisfiable?42 secDisclaimer. KwickAcademy is free study material for general learning and revision. Parts of it, including the voice-over, are produced with the help of AI tools and may contain errors; if you spot one, please tell us and we will correct it. Syllabus, marks and exam details follow the latest official board publications available to us, and boards can change them at any time, so always confirm against your board's official website and your school. Using this material does not guarantee any marks or result. Board names and trademarks belong to their owners; Kwickprep is not affiliated with or endorsed by any examination board. We never ask for passwords, OTPs or ID numbers. Your progress is saved only in this browser. Full disclaimer · Privacy