Question

for every set A, A unionA=​

Answer 1

Union is basically the grouping of the elements of the two sets upon which the union operator is applied.

Thus, AUA = A

The union of set A with itself gives the set A.

Let's try and proof this.

Consider a set A = {a, b, c, d}

Thus, AUA = {a,b,c,d}U{a,b,c,d}

= {a,b,c,d}

= A

Hence, AUA = A