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☼ Equal Sets : Two sets A and B are said to be equal, if each and every element of A is in B and each and every element of B is in A.
In this case we can write, A = B….
☼ Finite & Infinite Sets : A set in which the process of counting of elements surely comes to an end or one can take an upper limit for that set, is called a finite set
A set which is not finite is known as an infinit…
☼ Singleton Set : A set consisting of a single element is called a singleton set.
e.g. { x / x + 5 = 7 } = { 2 }, which is a singleton set….
Roster Method ( Listing Method ) : Under this method, we just make a list of the objects of the set and put them within braces { }.
e.g. (i) If A is set of first five prime numbers, then A = { 2, 3, 5, 7,…
(8) What is the least number which is divisible by 2, 5, 6 and 9 and at the same time a perfect square ?
Soln. [ 2, 5, 6, 9 ] = LCM of 2, 5, 6 and 9 = 2
■Arithmetical Progression (A.P.) : If each term of a progression differs from its preceding term by a constant, then such a progression is called an arithmetical progression. This constant difference is known as common differen…