This page provides comprehensive Class 11 Maths Exemplar Chapter 1 Exercise 1.2 Solutions. Detailed step-by-step solutions for Class 11 Maths NCERT Exemplar Chapter 1 Sets Exercise 1.2. Free PDF download and interactive practice.
Exercise 1.2
Short Answer Type Questions (1-4)
Q1
Write the following sets in the roster form: (i) \(A = \{x : x \in R, 2x + 11 = 15\}\) (ii) \(B = \{x | x^2 = x, x \in R\}\) (iii) \(C = \{x | x \text{ is a positive factor of a prime number } p\}\)
If \(X = \{1, 2, 3\}\), if \(n\) represents any member of \(X\), write the following sets containing all numbers represented by (i) \(4n\) (ii) \(n+6\) (iii) \(\frac{n}{2}\)
If \(Y = \{1, 2, 3, \dots, 10\}\), and \(a\) represents any element of \(Y\), write the following sets, containing all the elements satisfying the given conditions. (i) \(a \in Y\) but \(a^2 \notin Y\) (ii) \(a+1 \in Y\) and \(a-1 \in Y\)
(i) \(a \in Y\) such that \(a^2 > 10\). Elements are 4 (16), 5 (25), ..., 10 (100). Set = \{4, 5, 6, 7, 8, 9, 10\}.
(ii) \(a+1 \le 10 \implies a \le 9\) and \(a-1 \ge 1 \implies a \ge 2\). So \(a \in \{2, 3, \dots, 9\}\).
$(i) {4, 5, 6, 7, 8, 9, 10} (ii) {2, 3, ..., 9}$
Fill in the Blanks (5-13)
Q5
The set \(\{x \in R : 1 \le x < 2\}\) can be written as ________.
Use interval notation. Square bracket for inclusive, parenthesis for exclusive.
Q6
When \(A = \phi\), then the number of elements in \(P(A)\) is ________.
\(n(A) = 0\). Number of elements in power set = \(2^{n(A)} = 2^0 = 1\).
$1$
Q7
If \(A\) and \(B\) are finite sets, such that \(A \subset B\), then \(n(A \cup B)\) is equal to ________.
If A is inside B, their union is just B.
Q8
If \(A\) and \(B\) are finite sets, such that \(A \subset B\), then \(n(A \cap B)\) is equal to ________.
If A is inside B, their intersection is just A.
Q9
If \(A\) and \(B\) are any two finite sets, then \(n(A \cup B)\) is equal to ________.
Q10
\(A \cup B = A \cap B\) implies ________.
Union and intersection are equal only when the sets are identical.