Complex Conjugate
1. **Problem Statement:** Find the complex conjugate $A^*$ of the expression $$A = e^{i\phi}(e^{i\theta_1} - 1) + e^{i(\theta_1 + \theta_2)}(e^{i\theta_3} - 1).$$
2. **Recall the rule for complex conjugates:**
- The complex conjugate of $e^{ix}$ is $e^{-ix}$.
- The conjugate of a sum is the sum of the conjugates.
3. **Apply conjugate to each term:**
$$A^* = \overline{e^{i\phi}(e^{i\theta_1} - 1)} + \overline{e^{i(\theta_1 + \theta_2)}(e^{i\theta_3} - 1)}.$$
4. **Use conjugate properties:**
$$A^* = e^{-i\phi}(e^{-i\theta_1} - 1) + e^{-i(\theta_1 + \theta_2)}(e^{-i\theta_3} - 1).$$
5. **Final answer:**
$$\boxed{A^* = e^{-i\phi}(e^{-i\theta_1} - 1) + e^{-i(\theta_1 + \theta_2)}(e^{-i\theta_3} - 1)}.$$