Laws of algebra of set THEOREM 1 (Idempotent Laws) For any set A (i) A ∪ A = A (ii) A ∩ A = A PROOF (i) A ∪ A= { x : x ∈ A or x ∈ A} ={x : x ∈ A} = A (ii) A ∩ A = {x : x…
Macroscopic and Microscopic Approaches The behaviour of matter can be studied by two approaches 1. Macroscopic approach, 2. Microscopic approach 1. Macroscopic approach – In the macroscopic approach a certain quantity of matter is considered for study without knowing the behaviour of individual…
Venn diagrams The diagram drawn to represent sets are called Venn-diagram. In Venn-diagram the universal set U is represented by points within the rectangle and its subsets are represented points in closed curves (usually circles) within the rectangle. If a set A is a subset of a set B, then the circles representing A is…
Union of sets Let A and B be two sets. The union of A and B is the set of all those elements which belong either to A or to B or to both A and B. We denote A union B by notation “A ∪ B” Thus A∪B = { x : x ∈…
Theorem 3 The total number of subsets of a finite set containing n elements is 2ⁿ. Proof Let A be a finite set containing n elements.Let 0 ≤ r ≤ n. Consider those subset,of A that have r elements each.We know that the number of ways in which r elements can be chosen…
Pressure The molecules of a gas are in random motion. The rapidly moving molecules continually impact on the surface of the container and its effect is to produce a force over the surface. The force normal to unit area of surface is called pressure acting on the surface. The normal force exerted by the atmosphere…
