What is the minimum number of pairs to form a non - zero reflexive relation on a set of n elements?

What is the minimum number of carbon atoms required to form a cyclic compound.

Show that the relation R defined in the set A of all polygons as R={(P_1,P_2): P_1 and P_2 have the same number of sides },is an equivalence relation.What is the set of all elements in A related to the right angled triangle T with sides 3,4 and 5?

When a relation R on a set A is said to be reflexive

Show that each of the relation R in the set A={x in Z: 0 le xle12} ,given by R = {(a,b) : |a-b| is a multiple of 4} is an equivalence relation. Find the set of all elements related to 1 in each case.

The number of one-one function from a set containing 2 elements to a set containing 3 element is………a)2 b)3 c)6 d)8

What is the hardest element / form of an element in the world?

Which element among inert gases form, maximum number of compounds? Write the formula of one of the compounds formed by the element.

Show that each of the relation R in the set A={x in Z: 0lt= xlt=12} ,given by R = {(a,b) : a=b} is an equivalence relation. Find the set of all elements related to 1 in each case.