Iit jee book for maths preparation in last 3 months

First, solve all previous years Questions of JEE Advance. Then Go for Books for various Topics by different authors and You don't need to solve all the Problems, First, select a set of Problems and try to finish it in a time limit. Books by Amit M Agrawal are good for Calculus. You can go for SL Loney in Trigonometry and Coordinate Geometry. All Arihant books are good provided you stick to the syllabus and solve relevant problems.

By solving previous years Questions you can get Idea of questions being asked.

Hello Rithesh,
For Mathematics, you will need lot of practice. So, you should try to practice as much questions as you can.
Primarily student should refer to NCERT books as it is the best book for preparation and to understand the basic concept.
See, for JEE Advanced you will need in depth knowledge of the concepts. For better preparation and to score good marks you should refer to books such as-
Objective Mathematics By R.D. Sharma
Plane Trigonometry and Coordinate Geometry (Two Books) by S.L Loney
Problems in Calculus Of One Variable by I.A.Maron
Hall and Knight Higher Algebra
Integral Calculus for IIT-JEE by Amit M Agarwal (Arihant Publications)

Also, I would suggest that you should solve previous year question papers and give mock tests. It will help you in time management and to have an idea about the types of questions asked in the exam. First focus on JEE Main exam as after qualifying JEE Main then you will be eligible for JEE Advanced exam/
Good Luck!

Dear Rotherham,

Read books by H.C Verma or maths jee books by arihant publications.You can prefer tata mc graw hill books too.

All the best