Case 1 Let c be a real number which is not equal to any integer. for all real numbers close to c the value of the function is equal to [c]; i.e., . Also and hence the function is continuous at all real numbers not equal to integers.
Case 2 Let c be an integer. Then we can find a sufficiently small real number such that
This, in terms of limits mean that
Since these limits cannot be equal to each other for any c, the function is discontinuous at every integral point.

In a triangle ABC, a = 2b and then angle A is

He can invite any one friend in 6C1 ways= 6 ways:
He can invite any two friends in 6C2 ways = 15 ways
He can invite any three friends in 6C3 ways =20 ways
He can invite any 4 friends in 6C4ways = 15 ways
He can invite any 5 friends in 6C5 ways = 6 ways
He can invite all the 6 friends in 6C6 ways= 1 way.
Since any one of these could happen total possibilities are, 6+15+20+15+6+1 = 63.
