St. Britto Hr. Sec. School - Madurai
12th Maths Monthly Test - 3 ( Discrete Mathematics )-Aug 2020
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Let p: Jupiter is a planet and q: India is an island be any two simple statements. Give
verbal sentence describing each of the following statements.
(i) ¬p
(ii) p ∧ ¬q
(iii) ¬p ∨ q
(iv) p➝ ¬q
(v) p↔q -
Write the converse, inverse, and contrapositive of each of the following implication.
(i) If x and y are numbers such that x = y, then x2= y2
(ii) If a quadrilateral is a square then it is a rectangle. -
Construct the truth table for the following statements. ¬p ∧ ¬q
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Let A={a+\(\sqrt{5}\) b:a,b∈Z}. Check whether the usual multiplication is a binary operation on A.
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Examine the binary operation (closure property) of the following operations on the respective sets (if
it is not, make it binary) a ∗ b = \(\left(\frac{a-1}{b-1} \right)\), ∀a, b ∈ Q -
Write the statements in words corresponding to ¬p, p ∧ q , p ∨ q and q ∨ ¬p, where p is ‘It is cold’ and
q is ‘It is raining.’ -
Which one of the following sentences is a proposition?
(i) 4 + 7 =12
(ii) What are you doing?
(iii) 3n ≤ 8,1 n ∈ N
(iv) Peacock is our national bird
(v) How tall this mountain is! -
Determine whether ∗ is a binary operation on the sets given below.
a*b=b=a.|b| on R -
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Determine whether ∗ is a binary operation on the sets given below.
(A*v)=a√b is binary on R -
How many rows are needed for following statement formulae?
(( p ∧ q) ∨ (¬r ∨¬s)) ∧ (¬ t ∧ v))
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Construct the truth table for the following statements.¬(p ∧ ¬q)
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Establish the equivalence property p ➝ q ≡ ㄱp ν q
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Show that q ➝ p ≡ ¬p ➝ ¬q
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Verify
(i) closure property
(ii) commutative property, and
(iii) associative property of the following operation on the given set.
(a*b) = ab ;∀a,b∈N (exponentiation property) -
On Z, define ⊗by (m⊗n)=mn+nm: ∀m, n∈Z. Is ⊗binary on Z?
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Verify whether the following compound propositions are tautologies or contradictions or contingency
(( p V q)∧ ~p) ➝ q -
Check whether the statement p➝(q➝p) is a tautology or a contradiction without using the truth
table. -
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Consider the binary operation ∗ defined on the set A = {a,b,c, d} by the following table:
*
a
b
c
d
a
a
c
b
d
b d a b c c
c
d
a
a
d
d
b
a
c
Is it commutative and associative?
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Verify the
(i) closure property,
(ii) commutative property,
(iii) associative property
(iv) existence of identity and
(v) existence of inverse for the arithmetic operation + on Z.
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Let *be defined on R by (a*b)=a+b+ab-7. is*binary on R? If so, find 3\(\left(\frac{-7}{15} \right)\).
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Define an operation∗ on Q as follows: a*b=\(\left(\frac{a+b}{2} \right)\); a,b ∈Q. Examine the existence of identity and the
existence of inverse for the operation * on Q. -
Construct the truth table for (p \(\bar { ∨ } \) q) ∧ (p\(\bar { ∨ } \) ¬q)
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Verify the
(i) closure property,
(ii) commutative property,
(iii) associative property
(iv) existence of identity and
(v) existence of inverse for the arithmetic operation + on
Ze = the set of all even integers -
Using the equivalence property, show that p ↔ q ≡ ( p ∧ q) v (ㄱp ∧ ㄱq)
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Establish the equivalence property connecting the bi-conditional with conditional: p ↔ q ≡ (p ➝ q)
∧ (q⟶ p) -
Let A be Q\{1}. Define ∗ on A by x*y = x + y − xy . Is ∗ binary on A? If so, examine the commutative
and associative properties satisfied by ∗ on A. -
Using truth table check whether the statements ¬(p V q) V (¬p ∧ q) and ¬p are logically equivalent.
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Let A be Q\{1}. Define ∗ on A by x*y = x + y − xy . Is ∗ binary on A? If so, examine the existence of
identity, existence of inverse properties for the operation ∗ on A. -
Let M = \(\left\{ \begin{pmatrix} x&x\\x&x \end{pmatrix}: x ∈ R − \{0\} \right\} \)and let * be the matrix multiplication. Determine whether M is
closed under ∗. If so, examine the commutative and associative properties satisfied by ∗ on M
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Verify
(i) closure property,
(ii) commutative property,
(iii) associative property,
(iv) existence of identity, and
(v) existence of inverse for the operation +5 on Z5 using table corresponding to addition modulo 5. -
Verify
(i) closure property,
(ii) commutative property,
(iii) associative property,
(iv) existence of identity, and
(v) existence of inverse for the operation ×11 on a subset A = {1,3,4,5,9}
of the set of remainders {0,1,2,3,4,5,6,7,8,9,10} -
Identify the valid statements from the following sentences.