maths book for competitive exams for class 11 & 12 combined on specific topics
Instead of taking Maths for Specific Topics, go with a Comprehensive Textbook, with Detailed Solved Examples, Explanations of Theorems, Formulas as well as one having excellent quality questions with solutions.
Five of the best books, which I prefer are
1. ML Khanna IIT Mathematics Vol 1&2
2. TMH Mathematics JEE Main&Adv
3. RS Agarwal Mathematics CBSE (Basics)
4. JEE MATHS Books By Arihant Publications
5. ML Agarwal Mathematics Class 11/12 (ISC)