Use the following information for next two questions:
A function $f(x)$ is said to be even if $f(-x) = f(x)$, and odd if $f(-x) = -f(x)$. Thus, for example, the function given by $f(x)=x^{2}$ is even, while the function given by $f(x)=x^{3}$ is odd. Using this definition, answer the following questions.
The sum of two odd functions
- is always an even function
- is always an odd function
- is sometimes odd and sometimes even
- may be neither odd nor even