[[Year One 問數]]Advance Maths Q20241129|| q2|| Integration|| arc cos|| HKDSE M2

[@DrKLiuMaths]

歡迎各位同學, 老師, 家長發表有意義的意見, 多多討論!!!

[@johntse5770]

Hi! Here's an alternative to this problem, which is also workable although it is slower:
Still integration by parts, but I will not do it directly from the start.
Let u = arccos x, cos u = x
So dx/du = - sin u, and dx = - sin u du
The integrand then becomes -u² sin u
and after performing by parts and undoing the substitution, the answer will be the same

[@DrKLiuMaths]

thx john