Mathematics and Statistics · Class 11 Commerce
Ch 1Sets and Relations — Class 11 Mathematics and Statistics, concept-first.
Much of the mathematics used in commerce and statistics — grouping customers by region, classifying products, describing the set of possible outcomes of a business decision — begins with the simple idea of a collection. A set is a well-defined collection of distinct objects.
Key concepts
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Sets and Their Representation
A set is a well-defined collection of distinct objects; its members are its elements, with meaning belongs to and meaning it does not. Because elements are distinct and unordered, is just and .
Most relevant Q&A
Chapter contents
The NCERT structure, section by section. Open a section to see its questions, then read the concept-first solution.
Sets and Their Representation
Much of the mathematics used in commerce and statistics — grouping customers by region, classifying products, describing the set of possible outcomes of a business decision — begins with the simple id…
Types of Sets
Once sets can be described, it is useful to classify them and to describe how one set can sit inside another.
Operations on Sets
Sets can be combined to form new sets. These operations are best pictured with a Venn diagram, in which the universal set is drawn as a rectangle and the sets inside it as circles; overlapping circles…
Ordered Pairs and Cartesian Product
So far the order of elements inside a set did not matter. But many real situations pair two things in a definite order — a product with its price, a year with its sales figure, an -coordinate with a -…
Relations
A relation captures the idea that some pairs of objects are connected by a rule while others are not — "is the price of", "is older than", "is the capital of".
Types of Relations
Relations defined on a single set (subsets of ) can have special structural properties. Three properties are especially important.
Exercises
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- Q10Write the set $B = \{x : x \in \mathbb{Z},\ -3 \le x < 2\}$ in roster form and state $n(B)$.Free
- Q11A set $A$ has $16$ subsets in total. How many elements does $A$ have, and how many proper subsets does it have?Free
- Q12For $U = \{1, 2, 3, \dots, 9\}$, $A = \{2, 4, 6, 8\}$ and $B = \{1, 2, 3, 4\}$, find (i) $A \cap B$, (ii) $A \cup B$, (iii) $B - A$, (iv) $(…Free
- Q13In a class of $40$ students, $30$ passed in Accountancy and $25$ passed in Economics; $20$ passed in both subjects. How many students passed…Preview
- Q14If $A = \{x, y\}$ and $B = \{1, 2, 3\}$, write $A \times B$ and state $n(A \times B)$.Preview
- Q15Let $A = \{1, 2, 3, 4, 5\}$. A relation $R$ on $A$ is defined by $R = \{(a, b) : b = a + 1\}$. Write $R$ in roster form and state its domain…Preview
- Q16On the set $A = \{1, 2, 3\}$, examine whether $R = \{(1, 1), (2, 2), (1, 2)\}$ is reflexive, symmetric and transitive.Preview
More questions
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- Example 1Write the set $A = \{x : x \in \mathbb{N},\ x \text{ is a divisor of } 12\}$ in roster form, and write the set $\{2, 4, 6, 8, 10\}$ in set-b…Free
- Example 2If $A = \{a, b, c\}$, write down the power set $P(A)$ and state $n(P(A))$ and the number of proper subsets of $A$.Free
- Example 3Let $U = \{1, 2, 3, \dots, 10\}$, $A = \{1, 2, 3, 4, 5\}$ and $B = \{4, 5, 6, 7\}$. Find (i) $A \cup B$, (ii) $A \cap B$, (iii) $A - B$, (iv…Free
- Example 4In a survey of $100$ investors, $60$ hold shares and $45$ hold mutual funds; $25$ hold both. How many hold (i) shares or mutual funds (at le…Preview
- Example 5For $U = \{1,2,3,4,5,6,7,8\}$, $A = \{1,2,3,4\}$ and $B = \{3,4,5,6\}$, verify De Morgan's law $(A \cup B)' = A' \cap B'$.Preview
- Example 6If $A = \{1, 2\}$ and $B = \{3, 4, 5\}$, find $A \times B$, $B \times A$, and $n(A \times B)$. Is $A \times B = B \times A$?Preview
- Example 7If $A \times B = \{(1, p),\ (1, q),\ (2, p),\ (2, q)\}$, find the sets $A$ and $B$.Preview
- Example 8Let $A = \{1, 2, 3, 4\}$ and $B = \{1, 4, 9, 16\}$. A relation $R$ from $A$ to $B$ is defined by $R = \{(a, b) : b = a^{2},\ a \in A,\ b \in…Preview
- Example 9On the set $A = \{1, 2, 3\}$, a relation is given by $R = \{(1,1),(2,2),(3,3),(1,2),(2,1)\}$. Determine whether $R$ is reflexive, symmetric…Preview