Depend on student's level. This class has to pass a test to get in. Because need kids to understand and not fail this class. I have no idea where is the online book. we rented text books each year. After study those books, my son could use the concepts to resolve some HS 微积分 questions. Of course HS teacher weren't happy because he wanted kids to resolve queations using 微积分 ( he thought only 微积分 can do). I had read those books and questions on each charpt. Questiones are very hard in those two books and I don't think HS math in China even get close to( I got HS education in China and one classmate went to Beijing University, math major).
But one of my son's best friend graduated from same HS, his math level is equal to my son's 5th grade level. His college math level was even lower than the one post on top. of course, he is not in a good college.
my son's math isn't best in his school. some students were much better than him in HS( a few). This is a normal HS and not selective HS.