Hi Studnet,

For JEE Mains 2020 Mathematics preparation TMH and Cengage by G Tewani  both are very good books. But if you want the best then let me tell you about both of them. TMH is a very good book for complete explanation of topics. However, Cengage by G Tewani is a very good book with lots of questions, the questions are of a good level and require efforts to solve.

So, only you have to choose which one will be the best book for you.

Refer here for more info - https://engineering.careers360.com/articles/best-books-for-jee-main

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck!