Question

Is the function `f(x) = sin x` even, odd or neither?

Answer 1

Odd

Explanation:

By definition, a function f is even if `f(-x)=f(x)`.
A function f is odd if `f(-x)=-f(x)`

Since `sin(-x)=-sinx`, it implies that sinx is an odd function.

That is why for example a half range Fourier sine series is said to be odd as well since it is an infinite sum of odd functions.