What does the U symbol mean in algebra?

Answer 1

The U symbol means "union". A union of two sets means that the distinct elements of each set are combined together. For example, the union of {1,2,3} and {4,5,6} is {1,2,3} U {4,5,6} = {1,2,3,4,5,6}. If a number is an element of both sets, the union of the sets will only contain one instance of that number. For example: {1,2,3} U {2,3,4} = {1,2,3,4}, and does NOT equal {1,2,2,3,3,4}.