Hi there. In response to your query the standard book you should go for both of them should be NCERT, as it's the basis of all the concepts. That being said here are some links to help you out:-
1. For VITEEE
https://www.google.com/url?sa=t&source=web&rct=j&url=https://engineering.careers360.com/articles/viteee-preparation-tips/amp&ved=2ahUKEwiJ45rbyr74AhVt4jgGHTiQAQwQtwJ6BAg5EAE&usg=AOvVaw1xIcVVh0W7H6ssGA8Rc5ms
2. For BITSAT
https://www.google.com/url?sa=t&source=web&rct=j&url=https://engineering.careers360.com/articles/best-books-for-bitsat/amp&ved=2ahUKEwii3ar6yr74AhUxyDgGHbABC08QFnoECAUQAQ&usg=AOvVaw3dIpVd-_q81uPUECCMZ1d-
Hope this answer helps; best wishes
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