Final answer:
The symbol '∉' indicates an object is not an element of a set, while the symbol '∈' shows that an object is an element of a set.
Step-by-step explanation:
In mathematics, specific symbols are used to describe the relationship between elements and sets. The symbol used to indicate that an object is not an element of a set is '∉'. For example, if we have a set A = {2, 4, 6}, and we want to express that 3 is not an element of set A, we would write it as 3 ∉ A.
Conversely, the symbol used to show that an object is an element of a set is '∈'. Following the previous example, if we intend to state that 4 is an element of set A, we would write 4 ∈ A. These notations help to clearly define the membership of elements within a set.