If f(t) = – f(– t) and f(t) satisfy the Dirichlet’s

If f(t) = – f(– t) and f(t) satisfy the Dirichlet’s conditions, then f (t) can be expanded in a Fourier series containing—

1. only sine terms
2. only cosine terms
3. cosine terms and a constant term
4. sine terms and a constant term

Since
f(t) = – f(– t)
Represents the condition of an odd function, which contains only sine terms.