Yes, solving previous years' question papers of the UPSC Mathematics optional subject can significantly help in improving your ability to handle complex problem-solving scenarios. Here's how:

1. Familiarity with Question Pattern:
- By solving previous years' question papers, you become familiar with the pattern and type of questions asked in the UPSC Mathematics optional subject.
- This familiarity helps you develop a better understanding of the topics and their application in real-life problem-solving scenarios.

2. Identification of Important Topics:
- Solving previous years' question papers enables you to identify the important topics that are frequently asked in the exams.
- By focusing on these topics, you can prioritize your preparation and allocate more time to mastering them.

3. Practice in Time-bound Environment:
- Solving previous years' question papers helps you practice solving problems within the allocated time limit, simulating the actual exam conditions.
- This improves your speed and accuracy in solving complex problems, which is crucial for the UPSC Mathematics optional subject.

4. Exposure to Diverse Problem Types:
- Previous years' question papers expose you to a wide range of problem types, covering various concepts and applications.
- By solving these diverse problems, you enhance your problem-solving skills and develop a deeper understanding of different mathematical concepts.

5. Self-Assessment and Gap Analysis:
- Solving previous years' question papers allows you to assess your own performance and identify any gaps in your knowledge or understanding.
- This self-assessment helps you focus on areas that require further improvement, enabling you to strengthen your overall preparation.

6. Confidence Building:
- Regularly solving previous years' question papers not only improves your problem-solving abilities but also boosts your confidence.
- As you become more comfortable with the exam pattern and the types of questions asked, you develop a sense of familiarity and assurance, which is vital during the actual exam.

Conclusion:
In conclusion, solving previous years' question papers of the UPSC Mathematics optional subject is an effective strategy to enhance your ability to handle complex problem-solving scenarios. It provides you with a comprehensive understanding of the exam pattern, helps you identify important topics, enables practice in a time-bound environment, exposes you to diverse problem types, allows self-assessment and gap analysis, and builds your confidence. Therefore, incorporating the practice of solving previous years' question papers into your preparation strategy can significantly contribute to your success in the UPSC Mathematics optional subject.