Hi Dear,

Based on past yera paper analysis, following chapters in mathematics holds most importance and  forms mazor part of the question paper. So you must study thoroughly following topics:

• Algebra
• Trigonometry
• Differential calculus and Integral calculus
• Analytical Geometry

You can refer following books for your preparation:

• NCERT Mathematics Textbooks of Class 11 and Class 12
• Pathfinder NDA & NA by Arihant Publications
• Chapterwise-Sectionwise Solved Papers NDA/NA by Arihant Publications
• Latest Manorama Yearbook
• Success Series General Knowledge by Sachchida Nand Jha

Good Luck