Advertisements
Advertisements
प्रश्न
Show that the statement “For any real numbers a and b, a2 = b2 implies that a = b” is not true by giving a counter-example.
Advertisements
उत्तर
The given statement can be written in the form of “if-then” as follows.
If a and b are real numbers such that a2 = b2, then a = b.
Let p: a and b are real numbers such that a2 = b2.
q: a = b
The given statement has to be proved false. For this purpose, it has to be proved that if p, then ∼q. To show this, two real numbers, a and b, with a2 = b2 are required such that a ≠ b.
Let a = 1 and b = –1
a2 = (1)2 = 1 and b2 = (– 1)2 = 1
∴ a2 = b2
However, a ≠ b
Thus, it can be concluded that the given statement is false.
संबंधित प्रश्न
Show that the statement
p: “If x is a real number such that x3 + 4x = 0, then x is 0” is true by
(i) direct method
(ii) method of contradiction
(iii) method of contrapositive
By giving a counter example, show that the following statements are not true.
q: The equation x2 – 1 = 0 does not have a root lying between 0 and 2.
Find out the sentence are statement and are not. Justify your answer.
Two non-empty sets have always a non-empty intersection.
Find out the sentence are statement and are not. Justify your answer.
There are 35 days in a month.
Find out the sentence are statement and are not. Justify your answer.
All real numbers are complex numbers.
Write the negation of the statement:
The sun is cold.
I will not go to school.
Both the diagonals of a rectangle have the same length.
Write the component statement of the compound statement and check whether the compound statement is true or false:
To enter into a public library children need an identity card from the school or a letter from the school authorities.
Determine whether the compound statement are true or false:
Delhi is in England and 2 + 2 =5.
Write the negation of statement:
For every x ϵ N, x + 3 < 10
Write the negation of statement:
There exists x ϵ N, x + 3 = 10
Write of the statement in the form "if p, then q".
It rains only if it is cold.
Check the validity of the statement:
p : 100 is a multiple of 4 and 5.
Check the validity of the statement:
r : 60 is a multiple of 3 or 5.
statement are true and false? In each case give a valid reason for saying so
p : Each radius of a circle is a chord of the circle.
Rewrite the following statements in the form of conditional statements:
Ramesh will get dessert only if he eats his dinner.
Express in English, the statement p → q, where
p: It is raining today
q: 2 + 3 > 4
Form the biconditional of the following statements :
p: Today is 14th of August
q: Tomorrow is Independence day
Translate the following biconditional into symbolic form:
“ABC is an equilateral triangle if and only if its each interior angle is 60°”
Check the validity of the statements:
s: 60 is a multiple of 3 or 5.
Which of the following sentences are statements? Justify
A triangle has three sides.
Which of the following sentences are statements? Justify
0 is a complex number.
Which of the following sentences are statements? Justify
Sky is red.
Which of the following sentences are statements? Justify
Every set is an infinite set.
Which of the following sentences are statements? Justify
Where is your bag?
Find the component statements of the following compound statements.
The number 100 is divisible by 3, 11 and 5.
Find the component statements of the following compound statements.
Chandigarh is the capital of Haryana and U.P.
Find the component statements of the following compound statements.
`sqrt(7)` is a rational number or an irrational number.
Find the component statements of the following compound statements.
Plants use sunlight, water and carbon dioxide for photosynthesis.
Translate the following statements into symbolic form
Rahul passed in Hindi and English.
Translate the following statements into symbolic form
x and y are even integers.
Form the biconditional statement p ↔ q, where
p: A natural number n is odd.
q: Natural number n is not divisible by 2.
Identify the Quantifiers in the following statements.
For every natural number x, x + 1 is also a natural number.
Identify the Quantifiers in the following statements.
There exists a triangle which is not an isosceles triangle.
Identify the Quantifiers in the following statements.
For all negative integers x, x 3 is also a negative integers.
Check the validity of the following statement.
q: 131 is a multiple of 3 or 11
The negation of the statement “7 is greater than 8” is ______.
The negation of the statement “Plants take in CO2 and give out O2 ” is ______.
