1.简单
写出了 (¬(p ∨ r) → q) ↔ (¬p → q) 的完整真值表。在多少行 N 中 p = 1 且 q = 0?
(¬(p ∨ r) → q) ↔ (¬p → q)
N =
2.简单
真值表中恰有一行使 ((a ↔ b) ∧ (a → c)) → (c ∨ b) 为假。点选这一行。
((a ↔ b) ∧ (a → c)) → (c ∨ b)
- 1a = 1, b = 1, c = 1
- 2a = 1, b = 1, c = 0
- 3a = 1, b = 0, c = 1
- 4a = 1, b = 0, c = 0
- 5a = 0, b = 1, c = 1
- 6a = 0, b = 1, c = 0
- 7a = 0, b = 0, c = 1
- 8a = 0, b = 0, c = 0
3.中等
在其真值表的 8 行中,(r → p) → ¬(p ∧ ¬(r ∧ q)) 在多少行为真?把这个数记作 N。
(r → p) → ¬(p ∧ ¬(r ∧ q))
N =
4.中等
在其真值表的 8 行中,((b ↔ a) ∨ c) ∧ ¬(a → (b → c)) 在多少行为真?把这个数记作 N。
((b ↔ a) ∨ c) ∧ ¬(a → (b → c))
N =
5.困难
前提为 q → (p ∨ r); q、结论为 p 的论证是无效的。点选真值表中作为反例的那一行。
q → (p ∨ r)q∴ p
- 1p = 1, q = 1, r = 1
- 2p = 1, q = 1, r = 0
- 3p = 1, q = 0, r = 1
- 4p = 1, q = 0, r = 0
- 5p = 0, q = 1, r = 1
- 6p = 0, q = 1, r = 0
- 7p = 0, q = 0, r = 1
- 8p = 0, q = 0, r = 0
6.困难
把否定完全移到内部之后,哪个命题与 ¬∀x (A(x) → ∃y R(x, y)) 等价?点选它。
¬∀x (A(x) → ∃y R(x, y))
- 1∀x (A(x) ∧ ∀y ¬R(x, y))
- 2∃x (A(x) ∧ ∀y ¬R(x, y))
- 3∃x (A(x) → ∀y ¬R(x, y))
- 4∃x (¬A(x) ∧ ∃y R(x, y))
答案
- 1. N = 2
- 2. a = 0, b = 0, c = 0
- 3. N = 5
- 4. N = 1
- 5. p = 0, q = 1, r = 1
- 6. ∃x (A(x) ∧ ∀y ¬R(x, y))
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