8/26/25, 8:03 AM WGU D420 Discrete Math 1 Exam (2025/2026) Updated: EXAM QUESTIONS WITH ACCURATE ANSWERS | GET IT RIGHT!! Fla…
WGU D420 Discrete Math 1 Exam (2025/2026)
Updated: EXAM QUESTIONS WITH ACCURATE
ANSWERS | GET IT RIGHT!!
Save
Terms in this set (212)
One or the other, but not both.
Exclusive or. ⊕
We can go to the park or the movies.
inclusive or is a: disjunction
1. ¬ (not)
2. ∧ (and)
Order of operations in
3. ∨ (or)
absence of parentheses.
the rule is that negation is applied first, then
conjunction, then disjunction:
truth table with three see pic
variables 2^3 rows
p→q
proposition
Ex: If it is raining today, the game will be cancelled.
q→p
Converse:
If the game is cancelled, it is raining today.
¬q → ¬p
Contrapositive
If the game is not cancelled, then it is not raining
today.
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,8/26/25, 8:03 AM WGU D420 Discrete Math 1 Exam (2025/2026) Updated: EXAM QUESTIONS WITH ACCURATE ANSWERS | GET IT RIGHT!! Fla…
¬p → ¬q
Inverse:
If it is not raining today, the game will not be
cancelled.
p↔q
true when P and Q have the same truth value.
biconditional
see truth table pic.
ex.
free variable P(x)
the variable is free to take any value in the domain
∀x P(x)
bound variable
bound to a quantifier.
the variable x in P(x) is bound
In the statement (∀x P(x)) the variable x in Q(x) is free.
∧ Q(x), this statement is not a proposition cause of the free
variable.
summary of De Morgan's ¬∀x P(x) ≡ ∃x ¬P(x)
laws for quantified ¬∃x P(x) ≡ ∀x ¬P(x)
statements.
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, 8/26/25, 8:03 AM WGU D420 Discrete Math 1 Exam (2025/2026) Updated: EXAM QUESTIONS WITH ACCURATE ANSWERS | GET IT RIGHT!! Fla…
see pic.
In order to use a truth table to establish the validity of
an argument, a truth table is constructed for all the
hypotheses and the conclusion.
A valid argument is a guarantee that the conclusion is
true whenever all of the hypotheses are true.
using a truth table to If when the hypotheses are true, the conclusion is not,
establish the validity of an then it is invalid.
argument
the argument works if every time the hypotheses
(anything above the line) are true, the conclusion is
also true.
hypotheses dont always all need to be true, see
example. but every time all the hypotheses are true,
the conclusion needs to be true as well.
rules of inference. see pic.
theorem any statement that you can prove
A proof consists of a series of steps, each of which
follows logically from assumptions, or from previously
proof
proven statements, whose final step should result in
the statement of the theorem being proven.
the proof of a theorem which are statements assumed to be true.
may make use of axioms:
proofs by exhaustion trying everything in the given universe.
https://quizlet.com/1068460504/wgu-d420-discrete-math-1-exam-20252026-updated-exam-questions-with-accurate-answers-get-it-right-flash-cards/?… 3/26
WGU D420 Discrete Math 1 Exam (2025/2026)
Updated: EXAM QUESTIONS WITH ACCURATE
ANSWERS | GET IT RIGHT!!
Save
Terms in this set (212)
One or the other, but not both.
Exclusive or. ⊕
We can go to the park or the movies.
inclusive or is a: disjunction
1. ¬ (not)
2. ∧ (and)
Order of operations in
3. ∨ (or)
absence of parentheses.
the rule is that negation is applied first, then
conjunction, then disjunction:
truth table with three see pic
variables 2^3 rows
p→q
proposition
Ex: If it is raining today, the game will be cancelled.
q→p
Converse:
If the game is cancelled, it is raining today.
¬q → ¬p
Contrapositive
If the game is not cancelled, then it is not raining
today.
https://quizlet.com/1068460504/wgu-d420-discrete-math-1-exam-20252026-updated-exam-questions-with-accurate-answers-get-it-right-flash-cards/?… 1/26
,8/26/25, 8:03 AM WGU D420 Discrete Math 1 Exam (2025/2026) Updated: EXAM QUESTIONS WITH ACCURATE ANSWERS | GET IT RIGHT!! Fla…
¬p → ¬q
Inverse:
If it is not raining today, the game will not be
cancelled.
p↔q
true when P and Q have the same truth value.
biconditional
see truth table pic.
ex.
free variable P(x)
the variable is free to take any value in the domain
∀x P(x)
bound variable
bound to a quantifier.
the variable x in P(x) is bound
In the statement (∀x P(x)) the variable x in Q(x) is free.
∧ Q(x), this statement is not a proposition cause of the free
variable.
summary of De Morgan's ¬∀x P(x) ≡ ∃x ¬P(x)
laws for quantified ¬∃x P(x) ≡ ∀x ¬P(x)
statements.
https://quizlet.com/1068460504/wgu-d420-discrete-math-1-exam-20252026-updated-exam-questions-with-accurate-answers-get-it-right-flash-cards/?… 2/26
, 8/26/25, 8:03 AM WGU D420 Discrete Math 1 Exam (2025/2026) Updated: EXAM QUESTIONS WITH ACCURATE ANSWERS | GET IT RIGHT!! Fla…
see pic.
In order to use a truth table to establish the validity of
an argument, a truth table is constructed for all the
hypotheses and the conclusion.
A valid argument is a guarantee that the conclusion is
true whenever all of the hypotheses are true.
using a truth table to If when the hypotheses are true, the conclusion is not,
establish the validity of an then it is invalid.
argument
the argument works if every time the hypotheses
(anything above the line) are true, the conclusion is
also true.
hypotheses dont always all need to be true, see
example. but every time all the hypotheses are true,
the conclusion needs to be true as well.
rules of inference. see pic.
theorem any statement that you can prove
A proof consists of a series of steps, each of which
follows logically from assumptions, or from previously
proof
proven statements, whose final step should result in
the statement of the theorem being proven.
the proof of a theorem which are statements assumed to be true.
may make use of axioms:
proofs by exhaustion trying everything in the given universe.
https://quizlet.com/1068460504/wgu-d420-discrete-math-1-exam-20252026-updated-exam-questions-with-accurate-answers-get-it-right-flash-cards/?… 3/26
