For each function $$f(x)$$, say which of the choices are anti-derivatives $$F(x)$$.

• $$f(x) = x$$
1. $$F(x) = 2 x + 3.5$$
2. $$F(x) = 2 x^2 - 1$$
3. $$F(x) = \frac{1}{2} x^2 + 5$$
4. $$F(x) = \frac{1}{2} x$$
• $$f(x) = e^{-k x} \sin(\frac{2 \pi}{P} x)$$
1. $$F(x) = - \frac{P e^{-kx}\left(k P \sin(\frac{2\pi}{P}x) + 2 \pi \cos(\frac{2 \pi}{P}x) \right)}{k^2 P^2 + 4 \pi^2}$$