Question: Find $f'(0)$ when $f(x) = 2 \sin x + \sin^2 x$.
1. **State the problem:** We need to find the derivative of the function $f(x) = 2 \sin x + \sin^2 x$ at $x=0$.
2. **Recall the derivative rules:**
- The derivative of $\sin x$ is $\cos x$.
- Use the chain rule for $\sin^2 x = (\sin x)^2$.
3. **Find the derivative $f'(x)$:**
$$f'(x) = \frac{d}{dx} \left(2 \sin x + \sin^2 x\right) = 2 \cos x + 2 \sin x \cos x$$
4. **Evaluate $f'(0)$:**
$$f'(0) = 2 \cos 0 + 2 \sin 0 \cos 0 = 2 \times 1 + 2 \times 0 \times 1 = 2$$
5. **Final answer:**
$$f'(0) = 2$$