Even and odd at the origin


a. If ƒ(0) is defined and ƒ is an even function, is it necessarily true that ƒ(0) = 0? Explain.

Key Concepts

Even Functions

An even function is defined as a function f(x) that satisfies the condition f(-x) = f(x) for all x in its domain. This symmetry about the y-axis implies that the function takes the same value for both positive and negative inputs. A common example is f(x) = x², where f(-x) = (-x)² = x², confirming its evenness.

Function Value at the Origin

The value of a function at the origin, denoted as f(0), is simply the output of the function when the input is zero. For even functions, this value can be any real number, including zero. Thus, knowing that a function is even does not inherently dictate that f(0) must equal zero.

Implications of Evenness at Specific Points

While even functions exhibit symmetry, this property does not impose specific values at particular points unless additional conditions are met. For instance, if f(0) is defined and f is even, it can be any value, not just zero. Therefore, the assertion that f(0) must equal zero is incorrect without further constraints.